Coding Tutorials

Write a PHP script to input data into the textbox, count the number of digits and display result appropriately

noreply@blogger.com (Unknown) — Thu, 22 Aug 2024 16:47:00 +0000

<!DOCTYPE html>

<head>

<title>Count Digits</title>

</head>

<body>

<h1>Count Digits in Input</h1>

<label for="inputText">Enter text:</label>

</form>

<?php

if ($_SERVER["REQUEST_METHOD"] == "POST") {

// Get the input value

$inputText = $_POST['inputText'];

// Initialize the digit count

$digitCount = 0;

// Count the number of digits

for ($i = 0; $i < strlen($inputText); $i++) {

if (is_numeric($inputText[$i])) {

$digitCount++;

}

// Display the result

echo "<h2>Result:</h2>";

echo "<p>Number of digits: $digitCount</p>";

}

</body>

</html>

Explanation:

1. HTML Form: The form uses the `POST` method to send data to the same script.

2. PHP Script: The PHP block processes the form submission:

- Retrieve Input: It gets the input text from the form using `$_POST['inputText']`.

- Count Digits: A loop goes through each character of the input text, checking if it is a numeric character using `is_numeric()`. If it is, it increments the `$digitCount` variable.

- Display Result: The number of digits is displayed below the form.

3 Apps to Sell Internet Data and Earn Money

noreply@blogger.com (Unknown) — Sun, 04 Feb 2024 07:12:00 +0000

Best Apps to Sell Internet Data and Earn Money

Pawns.app

Pawns.app is a relatively new website that few people are aware of. Although several bloggers claim it is the best website for selling internet bandwidth.

They pay $0.20 for every one GB of shared data.

https://pawns.app/?r=453077

Grass.io

Unleash the power of unused network resources with the Grass extension for Google Chrome. This innovative tool allows you to earn points while sharing your surplus bandwidth, transforming unused digital potential into tangible rewards. Grass functions by gently harnessing a small fragment of your surplus network resources, always maintaining your internet pace and seamless browsing experience. This extension is designed with sophisticated algorithms that guarantee only extra resources are leveraged, thereby preserving your browsing quality and speed consistently.

https://app.getgrass.io/register/?referralCode=3Vm8Hj1mIqTlBPt

write a shell script to find the largest number with it’s position

noreply@blogger.com (Unknown) — Mon, 05 Jun 2023 08:08:00 +0000

solution 1:-

#!/bin/bash

# Prompt the user to enter the numbers

echo "Enter a list of numbers (space-separated):"

read -a numbers

# Initialize variables

largest=${numbers[0]}

position=0

solution 2:-

# Find the largest number and its position

for ((i=1; i<${#numbers[@]}; i++))

if (( ${numbers[i]} > largest ))

then

largest=${numbers[i]}

position=$i

done

# Display the largest number and its position

echo "The largest number is $largest at position $position."

#!/bin/bash

# Prompt the user to enter the numbers

echo "Enter a list of numbers (space-separated):"

read -a numbers

# Initialize variables

largest=-999999

position=-1

# Find the largest number and its position

for i in "${!numbers[@]}"

if (( ${numbers[i]} > largest ))

then

largest=${numbers[i]}

position=$i

done

# Display the largest number and its position

echo "The largest number is $largest at position $position."

Different Types of Multi-User Computer Systems

noreply@blogger.com (Unknown) — Mon, 05 Jun 2023 07:59:00 +0000

Different Types of Multi-User Computer Systems

There are several types of multi-user computers, each with its own characteristics and intended use. Here are a few common types:

1. Mainframe Computers: Mainframes are powerful, large-scale computers designed to handle the processing needs of multiple users simultaneously. They are often used in organizations that require extensive data processing, such as large corporations, government agencies, and research institutions.

2. Server Computers: Servers are computers that provide various services and resources to multiple users or clients over a network. They can handle tasks such as file storage, hosting websites, managing databases, and running applications. Servers typically have more processing power, storage capacity, and memory than individual user computers.

3. Time-Sharing Systems: Time-sharing systems allow multiple users to simultaneously access and utilize a computer's resources. Each user is allocated a specific time slice or "time-sharing slot" during which they can interact with the computer. This approach allows efficient resource utilization and makes it appear as though each user has exclusive access to the system.

4. Terminal-based Systems: Terminal-based systems involve a central computer or server that connects to multiple remote terminals. The terminals, which are usually simpler devices without extensive processing capabilities, allow users to access and interact with the central computer remotely. This approach enables multiple users to work on a single computer simultaneously.

5. Virtualization: Virtualization technology allows a single physical computer, known as the host, to function as multiple virtual machines (VMs), each with its own operating system and applications. Each VM can be used by a different user, providing a multi-user environment. This approach enables efficient use of hardware resources and allows for isolation between users.

6. Cloud Computing: Cloud computing involves accessing and utilizing computing resources, such as storage, processing power, and software applications, over the internet. Cloud platforms enable multiple users to share these resources simultaneously. Users can access their applications and data from different devices and locations, making it a flexible and scalable multi-user computing environment.

These are just a few examples of multi-user computer systems. The specific type of multi-user system chosen depends on the requirements of the organization or individuals using it, such as the number of users, the level of resource sharing needed, and the intended applications or services.

Python Program: Reverse a Word - Simple and Efficient Word Reversal in Python

noreply@blogger.com (Unknown) — Sun, 04 Jun 2023 16:43:00 +0000

Certainly! Here's a Python program that accepts a word from the user and reverses it:

```python

word = input("Enter a word: ")

reversed_word = word[::-1]

print("Reversed word:", reversed_word)

```

In this program, we use the `input()` function to prompt the user to enter a word. The input is stored in the `word` variable. We then use slicing with a step value of -1 (`[::-1]`) to reverse the characters in the word. The reversed word is stored in the `reversed_word` variable. Finally, we use the `print()` function to display the reversed word to the user.

Here's an example of how the program would run:

```

Enter a word: Python

Reversed word: nohtyP

```

Please note that this program assumes the user will input a single word without any spaces.

Understanding Process Schedulers: Optimizing Task Allocation and Resource Management in Operating Systems

noreply@blogger.com (Unknown) — Sun, 04 Jun 2023 16:38:00 +0000

Process schedulers are an essential component of an operating system that manages the allocation of system resources to running processes or tasks. They play a crucial role in ensuring efficient and fair execution of processes, maximizing CPU utilization, minimizing response time, and providing a balanced distribution of resources.

Process scheduling involves selecting the most suitable process from the pool of ready processes and allocating the CPU to it. The scheduling decision is made by the short-term scheduler or CPU scheduler. The primary objective of the scheduler is to ensure that the CPU is effectively utilized and processes are executed in a timely manner.

Different scheduling algorithms and policies can be employed by process schedulers, depending on the operating system and specific requirements. Some commonly used scheduling algorithms include:

1. First-Come, First-Served (FCFS): Processes are executed in the order they arrive in the ready queue. It is a non-preemptive algorithm, meaning once a process starts executing, it continues until it completes or gets blocked.

2. Round Robin (RR): Each process is given a fixed time slice or quantum to execute before being preempted and moved to the back of the queue. This algorithm provides fair scheduling and is often used in time-sharing systems.

3. Shortest Job Next (SJN) or Shortest Job First (SJF): The process with the smallest burst time is selected for execution. This algorithm aims to minimize the average waiting time and can be preemptive or non-preemptive.

4. Priority Scheduling: Each process is assigned a priority, and the CPU is allocated to the highest priority process. It can be preemptive or non-preemptive, and priorities can be based on factors like process type, deadlines, or system-defined parameters.

5. Multilevel Queue Scheduling: Processes are divided into multiple queues based on priority or other criteria. Each queue may have its own scheduling algorithm, allowing for different levels of scheduling policies for different types of processes.

The choice of a scheduling algorithm depends on various factors, including the nature of the workload, system responsiveness requirements, fairness considerations, and resource utilization goals.

It's important to note that the long-term scheduler or admission scheduler plays a role in process scheduling as well. It determines which processes should be admitted to the system, considering factors such as the degree of multiprogramming and available resources.

Overall, process schedulers are responsible for managing the execution of processes in an efficient and balanced manner, ensuring optimal utilization of system resources and meeting performance objectives.

Process Schedulers: Optimizing Task Allocation and Resource Management

noreply@blogger.com (Unknown) — Sun, 04 Jun 2023 16:33:00 +0000

Process schedulers are an integral part of an operating system responsible for managing and scheduling processes or tasks to efficiently utilize system resources. They ensure fair and efficient allocation of the CPU (Central Processing Unit) to running processes. There are different types of process schedulers, each with its own characteristics and objectives. The three main types of process schedulers are:

1. Long-term scheduler (Admission scheduler):

- Also known as the admission scheduler or job scheduler.

- Determines which processes should be admitted to the system from the pool of new processes.

- It focuses on the degree of multiprogramming or the number of processes that should be allowed to run concurrently.

- Typically, long-term schedulers are not invoked frequently and deal with processes in the secondary memory.

2. Short-term scheduler (CPU scheduler):

- Also known as the CPU scheduler or dispatcher.

- Determines which process from the ready queue should be executed next and allocates the CPU to that process.

- It aims to minimize the response time, maximize throughput, and ensure fairness in process execution.

- Short-term schedulers are invoked frequently (e.g., on every clock interrupt or when a process completes its execution or is blocked) to make scheduling decisions.

3. Medium-term scheduler:

- Optional scheduler present in some operating systems, not always implemented.

- Transfers processes from main memory to secondary storage or vice versa to manage memory resources.

- It is responsible for controlling the degree of multiprogramming by moving processes in and out of main memory, based on their priority or other criteria.

- The medium-term scheduler helps to maintain a good balance between the number of processes in memory and the available resources.

These schedulers work together to manage the lifecycle of processes and ensure efficient resource utilization within an operating system. They are designed to balance competing objectives such as maximizing CPU utilization, minimizing response time, providing fairness, and managing memory effectively. Different operating systems and scheduling algorithms employ various strategies to achieve these objectives, such as First-Come-First-Served (FCFS), Round Robin, Shortest Job Next (SJN), Priority Scheduling, and many others.

Python program to convert month name to a number of days

noreply@blogger.com (Unknown) — Tue, 26 Apr 2022 03:15:00 +0000

Python program to convert month name to a number of days

code:-

print("List of months: January, February, March, April, May, June, July, August, September, October, November, December")
month_name = input("Input the name of Month: ")
 
if month_name == "February":
    print("No. of days: 28/29 days")
elif month_name in ("April", "June", "September", "November"):
    print("No. of days: 30 days")
elif month_name in ("January", "March", "May", "July", "August", "October", "December"):
    print("No. of days: 31 day")
else:
    print("Wrong month name")

output:-

List of months: January, February, March, April, May, June, July, August, September, October, November, December
Input the name of Month: March
No. of days: 31 day
>>>

Top Anime Wallpaper Apps

noreply@blogger.com (Unknown) — Fri, 22 Apr 2022 13:24:00 +0000

Top 10 Anime Wallpaper Apps

If you like anime wallpapersYou have come to the right place, since in this article we show you which are the 10 best anime wallpaper applications, an ideal application for lovers of this genre, a genre that, far from perishing, continues to expand every year.

All the applications that we show you in this article are compatible with any terminal that runs Android 5.0 onwards. All of them are available for your download completely free and only one of them offers us in-app purchases.

I invite you to take a look at the list below these lines to find your anime backgrounds app favorite.

Anime Wallpaper

4K anime wallpapers, puts at our disposal a large number of wallpapers in both 4K resolution and Full HD resolution. Practically every week we will find a new update offering new wallpapers.

Unlike other applications of this type, Anime Wallpapers 4K is also compatible with the format of tablets, a function that very few other applications offer us. It includes a section that allows us to store all the wallpapers that we like the most so that we can change them quickly without having to spend long periods of time looking for which one we like.

Another interesting function that we do not find in other applications is the possibility of download the wallpapers to our smartphone that you like the most, a function that allows us to later share them through messaging applications, by email, post them on social networks.

Among the different characters and themes that this application offers us we find:

Anime Wallpaper is available for your download completely free, includes ads but no in-app purchases.

link:-

https://play.google.com/store/apps/details?id=com.somai.animeandgamingfreewallpaper

Python program to check whether an alphabet is a vowel or consonant

noreply@blogger.com (Unknown) — Mon, 18 Apr 2022 07:13:00 +0000

Python program to check whether an alphabet is a vowel or consonant

code:-

str = input("Input a letter of the alphabet: ")
 
if str in ('a', 'e', 'i', 'o', 'u', 'A', 'E', 'I', 'O', 'U', 'A', 'E'):
    print("%s is a vowel." % str)
else:
    print("%s is a consonant." % str)

output:-

Input a letter of the alphabet: a

a is a vowel.

>>>

Input a letter of the alphabet: b

b is a consonant.

>>>

Python program to check the validity of a password

noreply@blogger.com (Unknown) — Mon, 18 Apr 2022 07:05:00 +0000

Python program to check the validity of a password

Validation rules:-

At least 1 letter between [a-z] and 1 letter between [A-Z]

At least 1 number between [0-9]

At least 1 character from [$#@]

Minimum length 8 characters

code:-

import re
password= input("Input your password: ")
x = True
while x:  
    if (len(password)<8):
        break
    elif not re.search("[a-z]",password):
        break
    elif not re.search("[0-9]",password):
        break
    elif not re.search("[A-Z]",password):
        break
    elif not re.search("[$#@]",password):
        break
    elif re.search("\s",password):
        break
    else:
        print("Valid Password")
        x=False
        break
 
if x:
    print("Not a Valid Password")

output:-

Input your password: hello

Not a Valid Password

>>>

Input your password: hello12345@

Not a Valid Password

>>>

Input your password: Hello123@

Valid Password

>>>

5 Apps to Make Money by Sharing Your Internet

noreply@blogger.com (Unknown) — Sun, 16 Jan 2022 15:06:00 +0000

5 Apps to Make Money by Sharing Your Internet

1.IPRoyal

IPRoyal is a relatively new website that few people are aware of. Although several bloggers claim it is the best website for selling internet bandwidth.

They pay $0.20 for every one GB of shared data.

The website’s user experience is straightforward.

Furthermore, because few people are aware of the website, you will have a better chance of sharing more bandwidth.

2.Honeygain

Honeygain is a handy and excellent web service for selling internet bandwidth around the world. For every 10 Mb of data you share, you get one credit.

You must have 20,000 credits, which is equal to $20, in order to check out the payment.

They started collecting less bandwidth from each individual as their popularity grew. For every 10 GB of data you share, you get $1.

This website also gives $5 as a joining bonus. They also have a referral program where you can earn a little more by inviting other people.

You can also estimate your earnings per month on their website.

3.Peer2profit

Peer2profit is yet another fantastic peer-to-peer bandwidth-sharing network. Every month you can make $6 – $75. Remember, the larger your network, the more money you’ll make. This is one of the best options for sharing network bandwidth worldwide.

Python program to find those numbers which are divisible by 7 and multiple of 5, between 1500 and 2700

noreply@blogger.com (Unknown) — Fri, 07 Jan 2022 08:32:00 +0000

Python program to find those numbers which are divisible by 7 and multiple of 5, between 1500 and 2700

Example 1:-

nl=[]
for x in range(500, 1350):
    if (x%7==0) and (x%5==0):
        nl.append(str(x))
print (','.join(nl))

output:-

525,560,595,630,665,700,735,770,805,840,875,910,945,980,1015,1050,1085,1120,1155,1190,1225,1260,1295,1330

>>>

Example 2:-

for i in range(1500,2701):

    if i%7==0 and i%5==0:

        print(i)

output:-

1505

1540

1575

1610

1645

1680

1715

1750

1785

1820

1855

1890

1925

1960

1995

2030

2065

2100

2135

2170

2205

2240

2275

2310

2345

2380

2415

2450

2485

2520

2555

2590

2625Enter the lower range:10

Enter the upper range:1000

105

140

175

210

245

280

315

350

385

420

455

490

525

560

595

630

665

700

735

770

805

840

875

910

945

980

>>>

2660

2695

>>>

Example 3:-

lower=int(input("Enter the lower range:"))
upper=int(input("Enter the upper range:"))
for i in range (lower,upper+1):
    if(i%7==0 and i%5==0):
        print(i)

output:-

Python program that accepts a word from the user and reverse

noreply@blogger.com (Unknown) — Tue, 04 Jan 2022 12:32:00 +0000

Write a Python program that accepts a word from the user and reverse it

Example 1:-

word = input("Input a word to reverse: ")

for char in range(len(word) - 1, -1, -1):
  print(word[char], end="")

output:-

Input a word to reverse: word
drow
>>>

Example 2:-

# Python code to reverse a string
# using loop

def reverse(word):
 str = ""
 for i in word:
    str = i + str
 return str

word=input("enter the string: ")

print ("The original string is : ",end="")
print (word)

print ("The reversed string(using loops) is : ",end="")
print (reverse(word))

output:-

enter the string: hello
The original string is : hello
The reversed string(using loops) is : olleh

Example 3:-

Python Program to Reverse Words in a Given String in Python


def rev_words(string):  
    words = string.split(' ') 
    rev = ' '.join(reversed(words)) 
    return rev
 
s=input("enter the string: ")
print ("reverse: ",rev_words(s))

output:-

enter the string: hello world
reverse:  world hello
>>>

Example 4:-

Reverse a String in Python

txt = "Hello World"[::-1]
print(txt)
output:-

dlroW olleH

Tag:-

How to reverse a string in Python?

Python program to count the number of even and odd numbers from a series of numbers

noreply@blogger.com (Unknown) — Tue, 04 Jan 2022 07:26:00 +0000

Python program to count the number of even and odd numbers from a series of numbers

Example 1:- Count even or odd using for loop

numbers = (2,4,6,3,1,9,8,11)
count_odd = 0
count_even = 0
for x in numbers:
        if not x % 2:
             count_even+=1
        else:
             count_odd+=1
print("Number of even numbers :",count_even)
print("Number of odd numbers :",count_odd)

output:-

Number of even numbers : 4

Number of odd numbers : 4

>>>

Example 2:-

numbers = [10,2,4,3,5,68,93,3,9,4] 

even, odd= 0, 0

for i in numbers: 

    if i % 2 == 0: 

        even += 1

    else: 

        odd+= 1          

print("Even : ", even) 

print("Odd : ", odd)

output:-

Even :  5
Odd :  5
>>>

Count Even and Odd in List Using Lambda Function

Example 3-

numbers = [1,4,2,7,8,11,2,3,66]

even_list = list(filter(lambda x: (x % 2 == 0), numbers))

odd_list = list(filter(lambda x: (x % 2 != 0), numbers))

print("{0} even numbes and {1} odds.".format(len(even_list), len(odd_list)))

output:-

5 even numbes and 4 odds.

>>>

Python Program to Count Even and Odd Numbers in a List

Example 4:-

NumList = []
Even_count = 0
Odd_count = 0

Number = int(input("Please enter the Total Number of List Elements: "))
for i in range(1, Number + 1):
    value = int(input("Please enter the Value of %d Element : " %i))
    NumList.append(value)

for j in range(Number):
    if(NumList[j] % 2 == 0):
        Even_count = Even_count + 1
    else:
        Odd_count = Odd_count + 1

print("\nTotal Number of Even Numbers in this List =  ", Even_count)
print("Total Number of Odd Numbers in this List = ", Odd_count)

output:-

Please enter the Total Number of List Elements: 4

Please enter the Value of 1 Element : 3

Please enter the Value of 2 Element : 1

Please enter the Value of 3 Element : 6

Please enter the Value of 4 Element : 8

Total Number of Even Numbers in this List = 2

Total Number of Odd Numbers in this List = 2

>>>

Python Program to Count Even and Odd Numbers in a List using While loop

NumList = []
Even_count = 0
Odd_count = 0
j = 0

Number = int(input("Please enter the Total Number of List Elements: "))
for i in range(1, Number + 1):
    value = int(input("Please enter the Value of %d Element : " %i))
    NumList.append(value)

while(j < Number):
    if(NumList[j] % 2 == 0):
        Even_count = Even_count + 1
    else:
        Odd_count = Odd_count + 1
    j = j + 1

print("\nTotal Number of Even Numbers in this List =  ", Even_count)
print("Total Number of Odd Numbers in this List = ", Odd_count)

output:-

Please enter the Total Number of List Elements: 4
Please enter the Value of 1 Element : 3
Please enter the Value of 2 Element : 7
Please enter the Value of 3 Element : 8
Please enter the Value of 4 Element : 1

Total Number of Even Numbers in this List =   1
Total Number of Odd Numbers in this List =  3
>>>

JQuery Tutorial

noreply@blogger.com (Unknown) — Mon, 03 Jan 2022 13:59:00 +0000

jQuery Introduction

The purpose of jQuery is to make it much easier to use JavaScript on your website.

What You Should Already Know

Before you start studying jQuery, you should have a basic knowledge of:

HTML
CSS
JavaScript

What is jQuery?

· jQuery is a lightweight, "write less, do more", JavaScript library.

· The purpose of jQuery is to make it much easier to use JavaScript on your website.

· jQuery takes a lot of common tasks that require many lines of JavaScript code to accomplish, and wraps them into methods that you can call with a single line of code.

· jQuery also simplifies a lot of the complicated things from JavaScript, like AJAX calls and DOM manipulation.

· The jQuery library contains the following features:

ü HTML/DOM manipulation

ü CSS manipulation

ü HTML event methods

ü Effects and animations

ü AJAX

ü Utilities

Why jQuery?

· There are lots of other JavaScript frameworks out there, but jQuery seems to be the most popular, and also the most extendable.

· Many of the biggest companies on the Web use jQuery, such as:

ü Google

ü Microsoft

ü IBM

ü Netflix

jQuery Get Started

Adding jQuery to Your Web Pages

There are several ways to start using jQuery on your web site. You can:

Download the jQuery library from jQuery.com
Include jQuery from a CDN, like Google

Downloading jQuery

There are two versions of jQuery available for downloading:

Production version - this is for your live website because it has been minified and compressed
Development version - this is for testing and development (uncompressed and readable code)

Both versions can be downloaded from jQuery.com.

The jQuery library is a single JavaScript file, and you reference it with the HTML <script> tag (notice that the <script> tag should be inside the <head> section):

jQuery CDN

If you don't want to download and host jQuery yourself, you can include it from a CDN (Content Delivery Network).

Both Google and Microsoft host jQuery.

To use jQuery from Google or Microsoft, use one of the following:

Google CDN:

Microsoft CDN:

jQuery Syntax

· With jQuery you select (query) HTML elements and perform "actions" on them.

· The jQuery syntax is tailor-made for selecting HTML elements and performing some action on the element(s).

Basic syntax is: $(selector).action()

A $ sign to define/access jQuery
A (selector) to "query (or find)" HTML elements
A jQuery action() to be performed on the element(s)

Examples:

$(this).hide() - hides the current element.

$("p").hide() - hides all <p> elements.

$(".test").hide() - hides all elements with class="test".

$("#test").hide() - hides the element with id="test".

The Document Ready Event

· You might have noticed that all jQuery methods in our examples, are inside a document ready event:

$(document).ready(function(){

// jQuery methods go here...

});

· This is to prevent any jQuery code from running before the document is finished loading (is ready).

· It is good practice to wait for the document to be fully loaded and ready before working with it. This also allows you to have your JavaScript code before the body of your document, in the head section.

· Here are some examples of actions that can fail if methods are run before the document is fully loaded:

ü Trying to hide an element that is not created yet

ü Trying to get the size of an image that is not loaded yet

· There is even a shorter method for the document ready event:

$(function(){

// jQuery methods go here...
});

· Any of the method can be used.

jQuery Selectors

· jQuery selectors allow you to select and manipulate HTML element(s).

· jQuery selectors are used to "find" (or select) HTML elements based on their id, classes, types, attributes, values of attributes and much more.

· All selectors in jQuery start with the dollar sign and parentheses: $().

The element Selector

· The jQuery element selector selects elements based on the element name.

· You can select all <p> elements on a page like this:

$("p")

Example

· When a user clicks on a button, all <p> elements will be hidden:

$(document).ready(function(){
    $("button").click(function(){
        $("p").hide();
    });
});

The #id Selector

· The jQuery #id selector uses the id attribute of an HTML tag to find the specific element.

· An id should be unique within a page, so you should use the #id selector when you want to find a single, unique element.

· To find an element with a specific id, write a hash character, followed by the id of the HTML element:

$("#test")

Example

· When a user clicks on a button, the element with id="test" will be hidden:

$(document).ready(function(){
    $("button").click(function(){
        $("#test").hide();
    });
});

The .class Selector

· The jQuery class selector finds elements with a specific class.

· To find elements with a specific class, write a period character, followed by the name of the class:

$(".test")

Example

· When a user clicks on a button, the element with class="test" will be hidden

$(document).ready(function(){
    $("button").click(function(){
        $(".test").hide();
    });
});

More Examples of jQuery Selectors

Syntax	Description
$("*")	Selects all elements
$(this)	Selects the current HTML element
$("p.intro")	Selects all <p> elements with class="intro"
$("p:first")	Selects the first <p> element
$("ul li:first")	Selects the first <li> element of the first <ul>
$("ul li:first-child")	Selects the first <li> element of every <ul>
$("[href]")	Selects all elements with an href attribute
$("a[target='_blank']")	Selects all <a> elements with a target attribute value equal to "_blank"
$("a[target!='_blank']")	Selects all <a> elements without a target attribute value NOT equal to "_blank"
$(":button")	Selects all <button> elements and <input> elements of type="button"
$("tr:even")	Selects all even <tr> elements
$("tr:odd")	Selects all odd <tr> elements

Functions In a Separate File

If your website contains a lot of pages, and you want your jQuery functions to be easy to maintain, you can put your jQuery functions in a separate .js file.

When we demonstrate jQuery in this tutorial, the functions are added directly into the <head> section. However, sometimes it is preferable to place them in a separate file, like this (use the src attribute to refer to the .js file):

jQuery Event Methods

jQuery is tailor-made to respond to events in an HTML page.

What are Events?

· All the different visitor's actions that a web page can respond to are called events.

· An event represents the precise moment when something happens.

· Examples:

ü moving a mouse over an element

ü selecting a radio button

ü clicking on an element

· The term "fires/fired" is often used with events. Example: "The keypress event is fired, the moment you press a key".

· Here are some common DOM events:

Mouse Events	Keyboard Events	Form Events	Document/Window Events
click	keypress	submit	load
dblclick	keydown	change	resize
mouseenter	keyup	focus	scroll
mouseleave		blur	unload

jQuery Syntax For Event Methods

· In jQuery, most DOM events have an equivalent jQuery method.

· To assign a click event to all paragraphs on a page, you can do this:

$("p").click();

· The next step is to define what should happen when the event fires. You must pass a function to the event:

$("p").click(function(){
// action goes here!!
});

Example :

When a click event fires on a <p> element; hide the current <p> element

<html>

<head>

$(document).ready(function(){

$("p").click(function(){

$(this).hide();

});

</script>

</head>

<body>

<p>If you click on me, I will disappear.</p>

<p>Click me away!</p>

<p>Click me too!</p>

</body>

</html>

dblclick()

The dblclick() method attaches an event handler function to an HTML element.

mouseenter()

The mouseenter() method attaches an event handler function to an HTML element.

mouseleave()

The mouseleave() method attaches an event handler function to an HTML element.

mousedown()

The mousedown() method attaches an event handler function to an HTML element.

mouseup()

The mouseup() method attaches an event handler function to an HTML element.

hover()

The hover() method takes two functions and is a combination of the mouseenter() and mouseleave() methods.

focus()

The focus() method attaches an event handler function to an HTML form field.

blur()

The blur() method attaches an event handler function to an HTML form field.

The on() Method

The on() method attaches one or more event handlers for the selected elements.

jQuery Effects

jQuery hide() , show() & toggle()

· You can hide and show HTML elements with the hide() and show() methods:

· You can toggle between the hide() and show() methods with the toggle() method.

· Syntax:

$(selector).hide(speed,callback);
$(selector).show(speed,callback);

$(selector).toggle(speed,callback);

· The optional speed parameter specifies the speed of the hiding/showing, and can take the following values: "slow", "fast", or milliseconds.

The optional callback parameter is a function to be executed after the hide() or show() or toggle() method completes.

· Example:

$("#hide").click(function(){
$("p").hide();
});

$("#show").click(function(){
$("p").show();
});

$("button").click(function(){
$("p").toggle();
});

jQuery Fading Methods

With jQuery you can fade an element in and out of visibility.
jQuery has the following fade methods:

o fadeIn()

o fadeOut()

o fadeToggle()

o fadeTo()

· Syntax:

$(selector).fadeIn(speed,callback);
$(selector).fadeOut(speed,callback);

$(selector).fadeToggle(speed,callback);

$(selector).fadeTo(speed,opacity,callback);

The required speed parameter specifies the duration of the effect. It can take the following values: "slow", "fast", or milliseconds.
The required opacity parameter in the fadeTo() method specifies fading to a given opacity (value between 0 and 1).
The optional callback parameter is a function to be executed after the function completes.

· Example:

$("button").click(function(){
    $("#div1").fadeIn();
    $("#div2").fadeIn("slow");
    $("#div3").fadeIn(3000);
});

$("button").click(function(){
    $("#div1").fadeOut();
    $("#div2").fadeOut("slow");
    $("#div3").fadeOut(3000);
});

$("button").click(function(){
    $("#div1").fadeToggle();
    $("#div2").fadeToggle("slow");
    $("#div3").fadeToggle(3000);
});

$("button").click(function(){
    $("#div1").fadeTo("slow", 0.15);
    $("#div2").fadeTo("slow", 0.4);
    $("#div3").fadeTo("slow", 0.7);
});

jQuery Sliding Methods

With jQuery you can create a sliding effect on elements.
jQuery has the following slide methods:

slideDown()
slideUp()
slideToggle(

· Syntax:

$(selector).slideDown(speed,callback);
$(selector).slideUp(speed,callback);

$(selector).slideToggle(speed,callback);

· The optional speed parameter specifies the speed of the hiding/showing, and can take the following values: "slow", "fast", or milliseconds.

· The optional callback parameter is a function to be executed after the sliding completes.

· Example:

<html>

<head>

<script src="jquery-2.1.4.js"></script>

<script>

$(document).ready(function(){

$("#flip").click(function(){

$("#panel").slideToggle("slow");

});

</script>

<style>

#panel, #flip {

padding: 5px;

text-align: center;

background-color: #e5eecc;

border: solid 1px #c3c3c3;

}

#panel {

padding: 50px;

display : none;

}

</style>

</head>

<body>

<div id="flip">Click to slide the panel down and up </div>

<div id="panel">Hello world!</div>

</body>

</html>

jQuery Animations - The animate() Method

The jQuery animate() method is used to create custom animations.

Syntax:

$(selector).animate({params},speed,callback);

The required params parameter defines the CSS properties to be animated.
The optional speed parameter specifies the duration of the effect. It can take the following values: "slow", "fast", or milliseconds.
The optional callback parameter is a function to be executed after the animation completes.

· Example: The following example demonstrates a simple use of the animate() method; it moves a <div> element to the right, until it has reached a left property of 250px:

<html>

<head>

<script src="jquery-2.1.4.js"></script>

<script>

$(document).ready(function(){

$("button").click(function(){

$("div").animate({left: '250px' });

});

</script>

</head>

<body>

<button>Start Animation</button>

<p>By default, all HTML elements have a static position, and cannot be moved. To manipulate the position, remember to first set the CSS position property of the element to relative, fixed, or absolute!</p>

<div style="background:green;height:100px;width:100px;position:absolute;"></div>

</body>

</html>

jQuery stop() Method

The jQuery stop() method is used to stop an animation or effect before it is finished.
The stop() method works for all jQuery effect functions, including sliding, fading and custom animations.

Syntax:

$(selector).stop(stopAll,goToEnd);

The optional stopAll parameter specifies whether also the animation queue should be cleared or not. Default is false, which means that only the active animation will be stopped, allowing any queued animations to be performed afterwards.
The optional goToEnd parameter specifies whether or not to complete the current animation immediately. Default is false.
So, by default, the stop() method kills the current animation being performed on the selected element.
Example: The following example demonstrates the stop() method, with no parameters: <html>

<head>

<script src="jquery-2.1.4.js"></script>

<script>

$(document).ready(function(){

$("#flip").click(function(){

$("#panel").slideDown(5000);

});

$("#stop").click(function(){

$("#panel").stop();

});

</script>

<style>

#panel, #flip {

padding: 5px;

font-size: 18px;

text-align: center;

background-color: #555;

color: white;

}

#panel {

padding: 50px;

display: none;

}

</style>

</head>

<body>

<button id="stop">Stop sliding</button>

<div id="flip">Click to slide down panel</div>

<div id="panel">Hello world!</div>

</body>

</html>

jQuery Callback Functions

JavaScript statements are executed line by line. However, with effects, the next line of code can be run even though the effect is not finished. This can create errors.
To prevent this, you can create a callback function.
A callback function is executed after the current effect is 100% finished.

Syntax:

$(selector).hide(speed,callback);

Example:

The example below has a callback parameter that is a function that will be executed after the hide effect is completed:

$("button").click(function(){
    $("p").hide("slow", function(){
        alert("The paragraph is now hidden");
    });
});

The example below has no callback parameter, and the alert box will be displayed before the hide effect is completed:

$("button").click(function(){
$("p").hide(1000);
alert("The paragraph is now hidden");
});

jQuery - Chaining

With jQuery, you can chain together actions/methods.

Chaining allows us to run multiple jQuery methods (on the same element) within a single statement.
It allows us to run multiple jQuery commands, one after the other, on the same element(s).
To chain an action, you simply append the action to the previous action.
Example: The following example chains together the css(), slideUp(), and slideDown() methods

$("#p1").css("color","red")

.slideUp(2000)

.slideDown(2000);

jQuery HTML

jQuery - Get Content and Attributes

jQuery contains powerful methods for changing and manipulating HTML elements and attributes

There are three jQuery methods for DOM manipulation are:

text() - Sets or returns the text content of selected elements
html() - Sets or returns the content of selected elements (including HTML markup)
val() - Sets or returns the value of form fields

Example: The following example demonstrates how to get content with the jQuery text() and html() methods:

$("#btn1").click(function(){
alert("Text: " + $("#test").text());
});
$("#btn2").click(function(){
alert("HTML: " + $("#test").html());
});

The following example demonstrates how to get the value of an input field with the jQuery val() method:

$("#btn1").click(function(){
alert("Value: " + $("#test").val());
});

Get Attributes - attr()

The jQuery attr() method is used to get attribute values.

The following example demonstrates how to get the value of the href attribute in a link:

<html>

<head>

<script src="/jquery-2.1.4.js"></script>

<script>

$(document).ready(function(){

$("button").click(function(){

alert($("#g").attr("href"));

});

</script>

</head>

<body>

<p><a href="http://www.google.com" id="g">Google</a></p>

<button>Show href Value</button>

</body>

</html>

jQuery - Set Content and Attributes

We will use the same three methods from the previous page to set content:

text() - Sets or returns the text content of selected elements
html() - Sets or returns the content of selected elements (including HTML markup)
val() - Sets or returns the value of form fields
Example: The following example demonstrates how to set content with the jQuery text(), html(), and val() methods:

<html>

<head>

<script src="jquery/2.1.4.js"></script>

<script>

$(document).ready(function(){

$("#btn1").click(function(){

$("#test1").text("Hello world!");

});

$("#btn2").click(function(){

$("#test2").html("<b>Hello world!</b>");

});

$("#btn3").click(function(){

$("#test3").val("BHARUCH");

});

</script>

</head>

<body>

<p id="test1">This is a paragraph.</p>

<p id="test2">This is another paragraph.</p>

<p>Input field: <input type="text" id="test3" value="SURAT"></p>

<button id="btn1">Set Text</button>

<button id="btn2">Set HTML</button>

<button id="btn3">Set Value</button>

</body>

</html>

Set Attributes - attr()

The jQuery attr() method is also used to set/change single or multiple attribute values.
Example: The following example demonstrates how to change (set) the value of the href attribute in a link:

$("button").click(function(){
$("#g").attr("href", "http://www.google.com");
});

The following example demonstrates how to change (set) the multiple value of the href attribute in a link

$("button").click(function(){
    $("#g").attr({
        "href" : "http://www.google.com",
        "title" : "Google Website"
    });
});

jQuery - Add Elements

Following four jQuery methods are used to add new content:

append() - Inserts content at the end of the selected elements
prepend() - Inserts content at the beginning of the selected elements
after() - Inserts content after the selected elements
before() - Inserts content before the selected elements

append() Method

Inserts content AT THE END of the selected HTML elements.

<html>

<head>

$(document).ready(function(){

$("#btn1").click(function(){

$("p").append(" <b>Appended text</b>.");

});

$("#btn2").click(function(){

$("ol").append("<li>Appended item</li>");

});

</script>

</head>

<body>

<p>This is a paragraph.</p>

<p>This is another paragraph.</p>

<ol>

</ol>

<button id="btn1">Append text</button>

<button id="btn2">Append list items</button>

</body>

</html>

prepend() Method

Inserts content AT THE BEGINNING of the selected HTML elements.

$(document).ready(function(){

$("#btn1").click(function(){

$("p").prepend("<b>Prepended text</b>. ");

});

$("#btn2").click(function(){

$("ol").prepend("<li>Prepended item</li>");

});

after() and before() Methods

The jQuery after() method inserts content AFTER the selected HTML elements.
The jQuery before() method inserts content BEFORE the selected HTML elements.

<html>

<head>

$(document).ready(function(){

$("#btn1").click(function(){

$("img").before("<b>Before</b>");

});

$("#btn2").click(function(){

$("img").after("<i>After</i>");

});

</script>

</head>

<body>

<button id="btn1">Insert before</button>

<button id="btn2">Insert after</button>

</body>

</html>

jQuery - Remove Elements

To remove elements and content, there are mainly two jQuery methods:

remove() - Removes the selected element (and its child elements)
empty() - Removes the child elements from the selected element

remove() Method

The jQuery remove() method removes the selected element(s) and its child elements.

<html>

<head>

$(document).ready(function(){

$("button").click(function(){

$("#div1").remove();

});

</script>

</head>

<body>

This is some text in the div.

<p>This is a paragraph in the div.</p>

<p>This is another paragraph in the div.</p>

</div>

<br>

<button>Remove div element</button>

</body>

</html>

empty() Method

The jQuery empty() method removes the child elements of the selected element(s).

$(document).ready(function(){

$("button").click(function(){

$("#div1").empty();

});

jQuery Manipulating CSS

jQuery has several methods for CSS manipulation. We will look at the following methods:

addClass() - Adds one or more classes to the selected elements
removeClass() - Removes one or more classes from the selected elements
toggleClass() - Toggles between adding/removing classes from the selected elements
css() - Sets or returns the style attribute
Let us consider following style sheet example:

.important {
    font-weight: bold;
    font-size: xx-large;
}

.blue {
    color: blue;
}

jQuery addClass() Method

The following example shows how to add class attributes to different elements. Of course you can select multiple elements, when adding classes:

$("button").click(function(){
$("h1, h2, p").addClass("blue");
$("div").addClass("important");
});

You can also specify multiple classes within the addClass() method:

$("button").click(function(){
$("#div1").addClass("important blue");
});

jQuery removeClass() Method

The following example shows how to remove a specific class attribute from different elements:

$("button").click(function(){
$("h1, h2, p").removeClass("blue");
});

jQuery toggleClass() Method

The following example will show how to use the jQuery toggleClass() method. This method toggles between adding/removing classes from the selected elements:

$("button").click(function(){
$("h1, h2, p").toggleClass("blue");
});

jQuery css() Method

The css() method sets or returns one or more style properties for the selected elements.

Return a CSS Property

To return the value of a specified CSS property, use the following syntax:

css("propertyname");

The following example will return the background-color value of the FIRST matched element:

$(document).ready(function(){

$("button").click(function(){

alert("Background color = " + ("p").css("background-color"));

});

Set a CSS Property

To set a specified CSS property, use the following syntax:

css("propertyname","value");

The following example will set the background-color value for ALL matched elements:

$(document).ready(function(){

$("button").click(function(){

$("p").css("background-color", "yellow");

});

Set Multiple CSS Properties

To set multiple CSS properties, use the following syntax:

css({"propertyname":"value","propertyname":"value",...});

The following example will set a background-color and a font-size for ALL matched elements:

$("p").css({"background-color": "yellow", "font-size": "200%"});

jQuery Dimension Methods

jQuery has several important methods for working with dimensions:

width()
height()
innerWidth()
innerHeight()
outerWidth()
outerHeight()

jQuery width() and height() Methods

The width() method sets or returns the width of an element (excludes padding, border and margin).
The height() method sets or returns the height of an element (excludes padding, border and margin).
The following example returns the width and height of a specified <div> element:

<html>

<head>

$("document").ready(function(){

$("button").click(function(){

var txt = "";

txt += "Width of div: " + $("#div1").width() + "</br>";

txt += "Height of div: " + $("#div1").height();

$("#div1").html(txt);

});

</script>

<style>

#div1 {

height: 100px;

width: 300px;

padding: 10px;

margin: 3px;

border: 1px solid blue;

background-color: lightblue;

}

</style>

</head>

<body>

<br>

<button>Display dimensions of div</button>

<p>width() - returns the width of an element.</p>

<p>height() - returns the height of an element.</p>

</body>

</html>

jQuery innerWidth() and innerHeight() Methods

· The innerWidth() method returns the width of an element (includes padding).

· The innerHeight() method returns the height of an element (includes padding).

jQuery outerWidth() and outerHeight() Methods

The outerWidth() method returns the width of an element (includes padding and border).
The outerHeight() method returns the height of an element (includes padding and border).

The following example sets the width and height of a specified <div> element:

$("button").click(function(){
$("#div1").width(500).height(500);
});

jQuery Traversing

What is Traversing?

jQuery traversing, which means "move through", are used to "find" (or select) HTML elements based on their relation to other elements. Start with one selection and move through that selection until you reach the elements you desire.

The image below illustrates a family tree. With jQuery traversing, you can easily move up (ancestors), down (descendants) and sideways (siblings) in the family tree, starting from the selected (current) element. This movement is called traversing - or moving through - the DOM.

Illustration explained:

The <div> element is the parent of <ul>, and an ancestor of everything inside of it
The <ul> element is the parent of both <li> elements, and a child of <div>
The left <li> element is the parent of <span>, child of <ul> and adescendant of <div>
The <span> element is a child of the left <li> and a descendant of <ul> and <div>
The two <li> elements are siblings (they share the same parent)
The right <li> element is the parent of <b>, child of <ul> and adescendant of <div>
The <b> element is a child of the right <li> and a descendant of <ul> and <div>

Traversing the DOM

jQuery provides a variety of methods that allows us to traverse the DOM.
The largest category of traversal methods are tree-traversal.

jQuery Traversing - Ancestors

An ancestor is a parent, grandparent, great-grandparent, and so on.
With jQuery you can traverse up the DOM tree to find ancestors of an element.

Traversing Up the DOM Tree

Three useful jQuery methods for traversing up the DOM tree are:

parent()
parents()
parentsUntil()

jQuery parent() Method

The parent() method returns the direct parent element of the selected element.
This method only traverse a single level up the DOM tree.
The following example returns the direct parent element of each <span> elements:

<html>

<head>

<style>

.ancestors * {

display: block;

border: 2px solid lightgrey;

color: lightgrey;

padding: 5px;

margin: 15px;

}

</style>

$(document).ready(function(){

$("span").parent().css({"color": "red", "border": "2px solid red"});

});

</script>

</head>

<body>

<div style="width:500px;">div (great-grandparent)

<ul>ul (grandparent)

<li>li (direct parent)

</li>

</ul>

</div>

<div style="width:500px;">div (grandparent)

<p>p (direct parent)

</p>

</div>

</body>

</html>

jQuery parents() Method

The parents() method returns all ancestor elements of the selected element, all the way up to the document's root element (<html>).
The following example returns all ancestors of all <span> elements:

<html>

<head>

<style>

.ancestors * {

display: block;

border: 2px solid lightgrey;

color: lightgrey;

padding: 5px;

margin: 15px;

}

</style>

$("document").ready(function(){

$("span").parents().css({"color": "red", "border": "2px solid red"});

});

</script>

<body class="ancestors">body (great-great-grandparent)

<div style="width:500px;">div (great-grandparent)

<ul>ul (grandparent)

<li>li (direct parent)

</li>

</ul>

</div>

</body>

You can also use an optional parameter to filter the search for ancestors.
The following example returns all ancestors of all <span> elements that are <ul> elements:

$(document).ready(function(){

$("span").parents("ul").css({"color": "red", "border": "2px solid red"});

});

</script>

jQuery parentsUntil() Method

The parentsUntil() method returns all ancestor elements between two given arguments.
The following example returns all ancestor elements between a <span> and a <div> element:

$(document).ready(function(){

$("span").parentsUntil("div").css({"color": "red", "border": "2px solid red"});

});

</script>

jQuery Traversing - Descendants

· A descendant is a child, grandchild, great-grandchild, and so on.

· With jQuery you can traverse down the DOM tree to find descendants of an element.

Traversing Down the DOM Tree

· Two useful jQuery methods for traversing down the DOM tree are:

· children()

· find()

jQuery children() Method

· The children() method returns all direct children of the selected element.

· This method only traverse a single level down the DOM tree.

· The following example returns all elements that are direct children of each <div> elements:

<html>

<head>

<style>

.descendants * {

display: block;

border: 2px solid lightgrey;

color: lightgrey;

padding: 5px;

margin: 15px;

}

</style>

$("document").ready(function(){

$("div").children().css({"color": "red", "border": "2px solid red"});

});

</script>

</head>

<body>

<div class="descendants" style="width:500px;">div (current element)

<p>p (child)

<span>span (grandchild)</span>

</p>

<p>p (child)

<span>span (grandchild)</span>

</p>

</div>

</body>

</html>

jQuery find() Method

The find() method returns descendant elements of the selected element, all the way down to the last descendant.

<html>

<head>

<style>

.descendants * {

display: block;

border: 2px solid lightgrey;

color: lightgrey;

padding: 5px;

margin: 15px;

}

</style>

$("document").ready(function(){

$("div").find("span").css({"color": "red", "border": "2px solid red"});

});

</script>

</head>

<body>

<div class="descendants" style="width:500px;">div (current element)

<p>p (child)

<span>span (grandchild)</span>

</p>

<p>p (child)

<span>span (grandchild)</span>

</p>

</div>

</body>

</html>

jQuery Traversing - Siblings

Siblings share the same parent.
With jQuery you can traverse sideways in the DOM tree to find siblings of an element.
There are many useful jQuery methods for traversing sideways in the DOM tree:

· siblings()

· next()

· nextAll()

· nextUntil()

· prev()

· prevAll()

· prevUntil()

jQuery siblings() Method

The siblings() method returns all sibling elements of the selected element.
The following example returns all sibling elements of <h2>:

<html>

<head>

<style>

.siblings * {

display: block;

border: 2px solid lightgrey;

color: lightgrey;

padding: 5px;

margin: 15px;

}

</style>

$("document").ready(function(){

$("h2").siblings().css({"color": "red", "border": "2px solid red"});

});

</script>

</head>

<div>div (parent)

</div></body></html>

jQuery next() Method

The next() method returns the next sibling element of the selected element.

jQuery nextAll() Method

The nextAll() method returns all next sibling elements of the selected element.

jQuery nextUntil() Method

The nextUntil() method returns all next sibling elements between two given arguments.

jQuery prev(), prevAll() & prevUntil() Methods

The prev(), prevAll() and prevUntil() methods work just like the methods above but with reverse functionality: they return previous sibling elements (traverse backwards along sibling elements in the DOM tree, instead of forward).

jQuery Traversing - Filtering

Narrow Down The Search For Elements

The three most basic filtering methods are first(), last() and eq(), which allow you to select a specific element based on its position in a group of elements.

Other filtering methods, like filter() and not() allow you to select elements that match, or do not match, a certain criteria.

jQuery first() Method

The first() method returns the first element of the selected elements.

The following example selects the first <p> element inside the first <div> element:

<html>

<head>

$("document").ready(function(){

$("div p").first().css("background-color", "yellow");

});

</script>

</head>

<body>

<h1>Welcome to My Homepage</h1>

<p>This is the first paragraph in body.</p>

<p>This is the first paragraph in a div.</p>

<p>This is the last paragraph in a div.</p>

</div><br>

<p>This is the first paragraph in another div.</p>

<p>This is the last paragraph in another div.</p>

</div>

<p>This is the last paragraph in body.</p>

</body>

</html>

jQuery last() Method

The last() method returns the last element of the selected elements.

jQuery eq() method

The eq() method returns an element with a specific index number of the selected elements.

The index numbers start at 0, so the first element will have the index number 0 and not 1

<html>

<head>

$("document").ready(function(){

$("p").eq(1).css("background-color", "yellow");

});

</script>

</head>

<body>

<h1>Welcome to My Homepage</h1>

<p>My name is Donald (index 0).</p>

<p>Donald Duck (index 1).</p>

<p>I live in Duckburg (index 2).</p>

<p>My best friend is Mickey (index 3).</p>

</body>

</html>

jQuery filter() Method

The filter() method lets you specify a criteria. Elements that do not match the criteria are removed from the selection, and those that match will be returned.

<html>

<head>

$("document").ready(function(){

$("p").filter(".intro").css("background-color", "yellow");

});

</script>

</head>

<body>

<h1>Welcome to My Homepage</h1>

<p>My name is Donald.</p>

<p class="intro">I live in Duckburg.</p>

<p class="intro">I love Duckburg.</p>

<p>My best friend is Mickey.</p>

</body>

</html>

jQuery not() Method

The not() method returns all elements that do not match the criteria.

Python program to display the current date and time

noreply@blogger.com (Unknown) — Mon, 03 Jan 2022 08:30:00 +0000

Python program to print the current date and time

Python Dates

A date in Python is not a data type of its own, but we can import a module named datetime to work with dates as date objects.

example :-

import datetime

x = datetime.datetime.now()
print(x)

The strftime() Method

The datetime object has a method for formatting date objects into readable strings.

The method is called strftime(), and takes one parameter, format, to specify the format of the returned string:

Python program to display the current date and time

import datetime
now = datetime.datetime.now()
print ("Current date and time : ")
print (now.strftime("%Y-%m-%d %H:%M:%S"))

output:-

Current date and time :

2022-01-03 13:46:50

>>>

Get the current date and time

from datetime import datetime

now = datetime.now()
 
print("now =", now)

dt_string = now.strftime("%d/%m/%Y %H:%M:%S")
print("date and time =", dt_string)

output:-

now = 2022-01-03 13:50:59.575978

date and time = 03/01/2022 13:50:59

>>>

Python get current date without time

import datetime
now = datetime.date.today()
currentDate = datetime.datetime.strptime('01/08/2015','%d/%m/%Y').date()
print(currentDate)

output:-

2022-01-03

>>>

Python get current time in seconds

import time
milliseconds = int(round(time.time() * 1000))
print(milliseconds)

output:-

1641198498286
>>>

Software Process Models and Types

noreply@blogger.com (Unknown) — Mon, 03 Jan 2022 07:38:00 +0000

Software Process Models

A software process model is a standardized format for planning, organizing and running a development project.

It is a description of the sequence of activity carried out in a SE project.

A software process model is a simplified representation of a software process.

Each process model follows a particular life cycle in order to ensure success in process of software development

Some methodologies are sometimes known as software development life cycle(SDLC)methodologies

Requirement gathering and analysis

Design

Implementation or coding

Testing

Deployment

Maintenance

Types of process model is Waterfall model, Prototype model, spiral model incremental model, iterative model, RAD model etc.

Types of Software Process Model

Waterfall model
Incremental model
Spiral model
Prototype model

WATERFALL MODEL / LINEAR-SEQUENTIAL MODEL

The Waterfall Model was first Process Model to be introduced. It is also referred to as a linear-sequential life cycle model because it illustrates the software development process in a linear sequential flow.

In a waterfall model, each phase must be completed before the next phase can begin and there is no overlapping in the phases.

Waterfall model is the earliest SDLC approach that was used for software development. It is very simple to understand and use.

In "The Waterfall" approach, the whole process of software development is divided into separate phases. In Waterfall model, the outcome of one phase acts as the input for the next phase sequentially.

Following is a diagrammatic representation of different phases of waterfall model.

The sequential phases in Waterfall model are:

Requirement Gathering and analysis: All possible requirements of the system to be developed are captured in this phase and documented in requirement specification documentation.

System Design: The first phases are studied in this phase and system design is prepared. System Design helps in specifying hardware and system requirements and also helps in defining overall system architecture.

Implementation: With inputs from system design, the system is first developed in small
programs called units, which are integrated in the next phase.
o Each unit is developed and tested for its functionality, which is referred to as Unit
Testing.
Integration and Testing: All the units developed in the implementation phase are
integrated into a system after testing of each unit.
o Post (After) integration the entire system is tested for any faults and failures.
Deployment of system: Once the functional and non-functional testing is done, the
product is deployed in the customer environment or released into the market.
Maintenance: There are some issues, which come up in the client environment.
o To fix those issues maintenance is done. Also to enhance the product some better
versions are released. Maintenance is done to deliver these changes in the customer
environment.
When to use waterfall model
• Requirements are very well documented, clear and fixed.
• Product definition is stable (no change).
• Technology is understood and is not dynamic.
• There are no ambiguous requirements (no double meaning and confusion).
• Ample resources with required expertise are available to support the product.
• The project is short.

Advantages
• Simple and easy to understand and use.
• Easy to manage due to the rigidity (strictness) of the model. Each phase has specific
deliverables (output) and a review process.
• Phases are processed and completed one at a time.
• Works well for smaller projects where requirements are very well understood.
• Clearly defined stages.
• Well-understood milestones (objective or target).
• Easy to arrange tasks.
• Process and results are well document
Disadvantages
• No working software is produced until late during the life cycle.
• High amounts of risk and uncertainty.
• Not a good model for complex and ongoing projects.
• It is difficult to measure progress within stages.
• Cannot accommodate changing requirements.
• Adjusting scope during the life cycle can end a project.

Prototype Model:-

working prototype of the system should be built.
By using this prototype, the client can get an “actual feel” of the system, since the
interactions with prototype can enable the client to better understand the requirements of
the desired system.
Prototype is a working model of software with some limited functionality.
A prototype is a version of a system or part of the system that’s developed quickly to check
the customer’s requirements or feasibility of some design decisions.
So, a prototype is useful when a customer or developer is not sure of the requirements,
efficiency, business rules, response time, etc.
Diagram of Prototype model:

A Prototype model suggests that before carrying the development of the actual software, a

A prototype is a toy implementation of the system.

Prototyping is an attractive idea for complicated and large systems for which there is no

manual process or existing system to help determining the requirements.

In prototyping, the client is involved throughout the development process, which increases

the likelihood of client acceptance of the final implementation.

A software prototype can be used:

Prototype model should be used when the desired system needs to have a lot of

interaction with the end users.

• Typically, online systems, web interfaces have a very high amount of interaction with

end users, are best suited for Prototype model.

• Prototyping ensures that the end users constantly work with the system and provide a

feedback which is incorporated in the prototype to result in a useable system.

• They are excellent for designing good human computer interface systems.

Advantages of Prototype model:

• Customer can get quickly result.

• Users are actively involved in the development

• Testing is almost completed before build/development is completed.

• Errors can be detected much earlier.

• Quicker user feedback is available leading to better solutions.

• Missing functionality can be identified easily

Disadvantages of Prototype model:

• Time consuming and costly

• Insufficient requirement.

• Extra prototype is required.

• Leads to implementing and then repairing way of building systems.

• Practically, this methodology may increase the complexity of the system as scope of the

system may expand beyond original plans.

Spiral Model:-

The spiral model is also known as spiral lifecycle model.

This model of development combines the feature of the prototype and waterfall model

A spiral model is divided into a number of framework activities, also called task Regions.

Typically, there are six task regions. Software project repeatedly passes though these phases

in iterations called spiral.

Diagram of spiral model that contains six task regions:

1) Customer communication:

• In this tasks required to establish effective communication between developer and

customer.

2) Planning:

• In this tasks required defining resources, timelines, and other project related

information.

• Requirements are studied and gathered

• Review and walkthroughs to streamline the requirements.

• Finalize the list of documents.

• The project is review and a decision made whether to continue with a further loop of

the spiral.

• If it is decided to continue, plans are drawn up for the next phase of the project.

3) Risk analysis

• In this tasks required to assess both technical and management risks.

• In the risk analysis phase a process is undertaken to identify risk and alternate

solutions.

• A prototype is produced at the end of the risk analysis phase.

• If any risk is found during the risk analysis then alternate solutions are suggested

and implemented.

4) Engineering

• In this phase software is developed, along with testing at the end of the phase.

• Actual development and testing is done if the software takes place in this phase.

• It include coding, test case and test results, test summary report

5) Construction and release

• It is requires to construct, test, install, and provide user support (e.g., documentation

and training).

6)Customer evaluation

• Customers evaluate the software and provide their feedback and approval.

• Features implemented document

When to use Spiral model:

• When the project is large.

• Where software needs continuous risk evaluation.

• When costs and risk evaluation is important.

• For medium to high-risk projects

• Users are unsure of their needs

• Requirements are complex and require continuous classification.

• New product line.

Advantages of Spiral model:

• Risk evaluation is proper.

• High amount of risk analysis hence, avoidance of Risk is enhanced.

• Good for large and critical projects.

• Strong approval and documentation control.

• More and more features are added in a systematic way.

• Software is produced early in the software life cycle.

Disadvantages of Spiral model:

• It is costly for small model.

• Risk analysis is important phase so requires expert people.

• Project’s success is highly dependent on the risk analysis phase.

• Spiral may go infinitely.

• It is suitable for larger project and not beneficial for smaller projects.

Incremental model :-

In incremental model the whole requirement is divided into various builds.

Each module passes through the requirements, design, implementation and testing phases

Diagram of Incremental model:

Incremental model is a method of software development where the product is designed,

implemented and tested incrementally until the product is finished.

Each subsequent release of the module adds function to the previous release. The process

continues till the complete system is achieved.

When we work incrementally we are adding piece by piece but expect that each piece is

fully finished. Thus keep on adding the pieces until it’s complete.

When to use the Incremental model:

• This model can be used when the requirements of the complete system are clearly

defined and understood.

• Major requirements must be defined; however, some details can evolve with time.

• There is a need to get a product to the market early.

• A new technology is being used

Advantages of Incremental model:

• Generates working software quickly and early during the software life cycle.

• This model is more flexible – less costly to change scope and requirements.

• It is easier to test and debug during a smaller iteration.

• In this model customer can respond to each built.

• Lowers initial delivery cost.

• Easier to manage risk because risky pieces are identified and handled during it’s

iteration.

Disadvantages of Incremental model:

• Needs good planning and design.

• Needs a clear and complete definition of the whole system before it can be broken

down and built incrementally.

• Total cost is higher than waterfall.

• There are some high-risk features and goals.

PHP browser detection script

noreply@blogger.com (Unknown) — Mon, 03 Jan 2022 06:27:00 +0000

Write a simple PHP browser detection script

Example 1:-

<?php echo "Your User Agent is :" . $_SERVER ['HTTP_USER_AGENT']; ?>

output:-

Your-User Agent is: Mozilla/5.0 (Windows NT 6.1) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/35.0.1916.114 Safari/537.36

example 2:-


<?php
$agent = $_SERVER["HTTP_USER_AGENT"];

if( preg_match('/MSIE (\d+\.\d+);/', $agent) ) {
  echo "You're using Internet Explorer";
} else if (preg_match('/Chrome[\/\s](\d+\.\d+)/', $agent) ) {
  echo "You're using Chrome";
} else if (preg_match('/Edge\/\d+/', $agent) ) {
  echo "You're using Edge";
} else if ( preg_match('/Firefox[\/\s](\d+\.\d+)/', $agent) ) {
  echo "You're using Firefox";
} else if ( preg_match('/OPR[\/\s](\d+\.\d+)/', $agent) ) {
  echo "You're using Opera";
} else if (preg_match('/Safari[\/\s](\d+\.\d+)/', $agent) ) {
  echo "You're using Safari";
}
?>

output:-

You're using Chrome
example 3:-


<?php
function getBrowser() {

$user_agent = $_SERVER['HTTP_USER_AGENT'];
$browser = "N/A";

$browsers = array(
'/msie/i' => 'Internet explorer',
'/firefox/i' => 'Firefox',
'/safari/i' => 'Safari',
'/chrome/i' => 'Chrome',
'/edge/i' => 'Edge',
'/opera/i' => 'Opera',
'/mobile/i' => 'Mobile browser'
);

foreach ($browsers as $regex => $value) {
if (preg_match($regex, $user_agent)) { $browser = $value; }
}

return $browser;
}

echo "Browser: " . getBrowser();
?>

output :-

Browser: Chrome

Python program to access a function inside a function

noreply@blogger.com (Unknown) — Mon, 03 Jan 2022 04:35:00 +0000

Python program to access a function inside a function

A function defined inside another function is called a nested function. Nested functions can access variables of the enclosing scope.

In Python, these non-local variables are read-only by default and we must declare them explicitly as non-local (using nonlocal keyword) in order to modify them.

Example 1:-

def main(a):
        def add(b):
                nonlocal a
                a += 1
                return a+b
        return add
func= main(12)
print(func(12))

output:-

Example 2:-

def print_msg(msg):
    # This is the outer enclosing function

    def printer():
        # This is the nested function
        print(msg)

    printer()

# We execute the function
# Output: Hello
print_msg("Hello")

output:-

hello

Example 3:-

def outer():
    def inner():
        print("hello")

    inner()
outer()

output:-

hello

Example 4:-

pass value to nested function

def outer(n):
    def inner():
        print(n)

    inner()
outer(13)

output:-

Sell Internet Bandwidth For Earn Money – Sell Data For Passive Income

noreply@blogger.com (Unknown) — Sun, 02 Jan 2022 13:49:00 +0000

Sell Internet Bandwidth For Earn Money – Sell Data For Passive Income

1. FLUIDSTACK

FluidStack is one of the newer players in the bandwidth buying industry, and they operate as a CDN to distribute content to users from nearby networks to increase page load times and overall user experience.

Once you signup and install FluidStack’s software, they will detect when your computer is idle and use your bandwidth/CPU to serve content.

The fact that FluidStack uses your CPU instead of GPU helps limit power consumption, and the whole idea of their platform is to only use your computer when it’s idle and to limit how much power you end up using.

In general, here is how its bandwidth speed to payout ratio works:

>10MB/s upload speed – $5/month
Faster speeds – $10 per 100MB/s
200 MB/s upload speed – $20/month

On their website, FluidStack states that you’re basically guaranteed to earn between $5-$50/month with their software based on your internet speed.

Keep in mind, this is per IP address, so if you have multiple IPs for some reason you could theoretically double dip.

FluidStack pays out through PayPal and all outstanding balances are processed at the end of the month. FluidStack also plans on releasing some additional ways to earn in the future, including video transcoding and geo-proxies, which will pay more.

Additionally, FluidStack will be releasing a cloud gaming feature which will allow powerful gaming rigs to host cloud gaming services for as much as $100/month, although we will have to wait and see how this actually unfolds.

Edit: 03/01/2020: Fluidstack has announced that they are focusing on cloud computer customers with access to machines with GPU’s running Fluidstack on Linux.

This means that most customers running Windows OS to rent bandwidth will no longer be able to make money from Fluidstack. In contrast, Linux machines now have guaranteed monthly payments based on the following models:

Fluidstack supports multi-GPU machines and pays out per GPU. Plus, Fluidstack guarantees utilization of 10% or less per month to help manage electricity costs.

If you have a GPU on your processor and don’t mind running Linux (or already run it), Fluidstack is definitely an excellent way to earn passive income by renting your bandwidth.

However, if you don’t have a GPU and want a viable Fluidstack alternative, checkout the rest of the platforms in this list!

Checkout our Fluidstack review for all the latest info!

2. PACKETSTREAM

PacketStream is another peer-to-peer network where people can use other people’s IP addresses (for a price).

PacketStream allows users to become nodes in their network from anywhere in the world, provided you have a residential IP address.

If you sell your internet bandwidth through PacketStream, you earn $0.10/GB as the software runs in the background of your computer.

PacketStream charges buyers $1.00/GB, and part of the problem is that free platforms like TOR essentially allow users to browse the web anonymously as well. From what I gather, this means PacketStream is a bit weak on the buy side currently, so your earnings will probably be slow and steady.

Some users are also uninstalling Packetstream due to concerns over how their platform is used by customers, so I’d be a bit careful with this service/do more research.

PacketStream states that their main clients are businesses who need to test web applications/ads without running into IP bans or detection (which is pretty common with VPNs).

You can run PacketStream on Windows, Linux, and Mac, and payouts are done via PayPal once you reach $5.

join now

3. HONEYGAIN

Honeygain is one of the newer players in this industry, and the app has gotten a lot of love and hate in various Reddit communities.

With a global user base and the ability to be run on windows and android devices, Honeygain seems pretty appealing at first glance. After all, most software that allows you to sell bandwidth does not work on mobile devices.

However, Honeygain does have a $20 cashout threshold via PayPal, and they only pay $1USD/10GB of bandwidth used.

From what I’ve seen on Reddit, the buy side can be pretty limited, so earning performance is rather volatile. It seems like some users are cashing out $40+ a month while others can barely make a dollar.

What does the Honeygain app do? Is it safe?

The app facilitates proxy services to third parties, such as data scientists, Fortune 500, and other trustworthy companies. Is it safe? Yes! Your security is important to us. And as the queen bee knows her bees, we know what every partner uses their network for.

What is the minimum payout?

The minimum payout is 20USD.

Earn free $5 using this link click here

4.IPRoyal

IPRoyal is a relatively new website that few people are aware of. Although several bloggers claim it is the best website for selling internet bandwidth.

They pay $0.20 for every one GB of shared data.

The website’s user experience is straightforward.

Furthermore, because few people are aware of the website, you will have a better chance of sharing more bandwidth.

join now

5.Peer2profit

They also have a referral program. For every 30 referrals, they pay around $100. They have multiple payout platforms like Bitcoin, Ethereum, Litecoin, WebMoney, etc.

join now

Student Database Management System in C with Source Code

noreply@blogger.com (Unknown) — Sun, 02 Jan 2022 04:55:00 +0000

C Program to Store Information of Students Using Structure

Method 1:-

#include<stdio.h>
#include<conio.h>
struct student {
    char name[20];
    int roll;
    float marks;
} s[5];

int main() {
    int i,n;

  printf("Enter how many records you want to store:-");
  scanf("%d",&n);
    // storing information
    for (i = 0; i < n; ++i) {
        s[i].roll = i + 1;
        printf("\nEnter roll no: ");
        scanf("%d",&s[i].roll);
        printf("Enter first name: ");
        scanf("%s", s[i].name);
        printf("Enter marks: ");
        scanf("%f", &s[i].marks);
    }
    printf("Displaying Information:\n\n");

    // displaying information
    for (i = 0; i < n; ++i) {
        printf("\nRoll number: %d\n", i + 1);
        printf("First name: ");
        puts(s[i].name);
        printf("Marks: %.1f", s[i].marks);
        printf("\n");
    }
    return 0;
}

output:-

Enter how many records you want to store:-2

Enter roll no: 1
Enter first name: ram
Enter marks: 100

Enter roll no: 2
Enter first name: rahul
Enter marks: 90
Displaying Information:


Roll number: 1
First name: ram
Marks: 100.0

Roll number: 2
First name: rahul
Marks: 90.0

Method 2:-

#include <stdio.h>

struct student
{
    int rollno;
    char name[80];
    int marks;
};

void accept(struct student[], int);
void display(struct student[], int);
void search(struct student[], int, int);
int findMax(struct student[], int);
void toppers(struct student[], int);

int main()
{
    struct student data[20];
    int n, choice, rollno;

    printf("Number of records you want to enter? : ");
    scanf("%d", &n);
    accept(data, n);
    do
    {

        printf("\nResult Menu :\n");
        printf("Press 1 to display all records.\n");
        printf("Press 2 to search a record.\n");
        printf("Press 3 to display toppers names.\n");
        printf("Press 0 to exit\n");
        printf("\nEnter choice(0-3) : ");
        scanf("%d", &choice);
        switch (choice)
        {
            case 1:
                display(data, n);
                break;
            case 2:
                printf("Enter roll number to search : ");
                scanf("%d", &rollno);
                search(data, n, rollno);
                break;
            case 3:
                toppers(data, n);
        }
    }
    while (choice != 0);

    return 0;
}

void accept(struct student list[80], int s)
{
    int i;
    for (i = 0; i < s; i++)
    {
        printf("\nEnter data for Record #%d", i + 1);

        printf("\nEnter rollno : ");
        scanf("%d", &list[i].rollno);
        fflush(stdin);
        printf("Enter name : ");
        gets(list[i].name);

        printf("Enter marks : ");
        scanf("%d", &list[i].marks);
    } 
}

void display(struct student list[80], int s)
{
    int i;

    printf("\n\nRollno\tName\tMarks\n");
    for (i = 0; i < s; i++)
    {
        printf("%d\t%s\t%d\n", list[i].rollno, list[i].name, list[i].marks);
    } 
}

void search(struct student list[80], int s, int number)
{
    int i;

    for (i = 0; i < s; i++)
    {
        if (list[i].rollno == number)
        {
            printf("Rollno : %d\nName : %s\nMarks : %d\n", list[i].rollno,
                list[i].name, list[i].marks);
            return ;
        } 
    }
    printf("Record not Found\n");
}

int findMax(struct student list[], int s)
{
    int i, max;

    max = list[0].marks;
    for (i = 1; i < s; i++)
    {
        if (list[i].marks > max)
        {
            max = list[i].marks;
        } 
    }
    return max;
}

void toppers(struct student list[], int s)
{
    int i;
    for (i = 0; i < s; i++)
    {
        if (list[i].marks == findMax(list, s))
        {
            printf("%s\n", list[i].name);
        } 
    }
}

output:-

Number of records you want to enter? : 2

Enter data for Record #1

Enter rollno : 1

Enter name : rahul

Enter marks : 100

Enter data for Record #2

Enter rollno : 2

Enter name : ram

Enter marks : 90

Result Menu :

Press 1 to display all records.

Press 2 to search a record.

Press 3 to display toppers names.

Press 0 to exit

Enter choice(0-3) : 1

Rollno Name Marks

1 rahul 100

2 ram 90

Result Menu :

Press 1 to display all records.

Press 2 to search a record.

Press 3 to display toppers names.

Press 0 to exit

Enter choice(0-3) : 2

Enter roll number to search : 1

Rollno : 1

Name : rahul

Marks : 100

Result Menu :

Press 1 to display all records.

Press 2 to search a record.

Press 3 to display toppers names.

Press 0 to exit

Enter choice(0-3) : 3

rahul

Result Menu :

Press 1 to display all records.

Press 2 to search a record.

Press 3 to display toppers names.

Press 0 to exit

Enter choice(0-3) : 0

PHP Regular Expressions

noreply@blogger.com (Unknown) — Sat, 01 Jan 2022 12:54:00 +0000

PHP regular expressions

PHP regular expressions seems to be a quite complicated area especially if you are not an experienced Unix user. Historically regular expressions were originally designed to help working with strings under Unix systems.

Using regular expressions you can easy find a pattern in a string and/or replace it if you want. This is a very powerful tool in your hand, but be careful as it is slower than the standard string manipulation functions.

Regular expression types

There are 2 types of regular expressions:

POSIX Extended
Perl Compatible

The ereg, eregi, ... are the POSIX versions and preg_match, preg_replace, ... are the Perl version. It is important that using Perl compatible regular expressions the expression should be enclosed in the delimiters, a forward slash (/). However this version is more powerful and faster as well than the POSIX one.

The regular expressions basic syntax

To use regular expressions first you need to learn the syntax of the patterns. We can group the characters inside a pattern like this:

Normal characters which match themselves like hello
Start and end indicators as ^ and $
Count indicators like +,*,?
Logical operator like |
Grouping with {},(),[]

An example pattern to check valid emails looks like this:

Code:

^[a-zA-Z0-9._-]+@[a-zA-Z0-9-]+\.[a-zA-Z.]{2,5}$

The code to check the email using Perl compatible regular expression looks like this:

Code:

1.  $pattern = "/^[a-zA-Z0-9._-]+@[a-zA-Z0-9-]+\.[a-zA-Z.]{2,5}$/";

2.  $email   = "jim@demo.com";

3.

4.  if (preg_match($pattern,$email)) echo "Match";

5.  else echo "Not match";

PHP F1

And very similar in case of POSIX extended regular expressions:

Code:

1.  $pattern = "^[a-zA-Z0-9._-]+@[a-zA-Z0-9-]+\.[a-zA-Z.]{2,5}$";

2.  $email   = "jim@demo.com";

3.

4.  if (eregi($pattern,$email)) echo "Match";

5.  else echo "Not match";

PHP F1

Now let's see a detailed pattern syntax reference:

Regular expression (pattern)	Match (subject)	Not match (subject)	Comment
world	Hello world	Hello Jim	Match if the pattern is present anywhere in the subject
^world	world class	Hello world	Match if the pattern is present at the beginning of the subject
world$	Hello world	world class	Match if the pattern is present at the end of the subject
world/i	This WoRLd	Hello Jim	Makes a search in case insensitive mode
^world$	world	Hello world	The string contains only the "world"
world*	worl, world, worlddd	wor	There is 0 or more "d" after "worl"
world+	world, worlddd	worl	There is at least 1 "d" after "worl"
world?	worl, world, worly	wor, wory	There is 0 or 1 "d" after "worl"
world{1}	world	worly	There is 1 "d" after "worl"
world{1,}	world, worlddd	worly	There is 1 ore more "d" after "worl"
world{2,3}	worldd, worlddd	world	There are 2 or 3 "d" after "worl"
wo(rld)*	wo, world, worldold	wa	There is 0 or more "rld" after "wo"
earth\|world	earth, world	sun	The string contains the "earth" or the "world"
w.rld	world, wwrld	wrld	Any character in place of the dot.
^.{5}$	world, earth	sun	A string with exactly 5 characters
[abc]	abc, bbaccc	sun	There is an "a" or "b" or "c" in the string
[a-z]	world	WORLD	There are any lowercase letter in the string
[a-zA-Z]	world, WORLD, Worl12	123	There are any lower- or uppercase letter in the string
[^wW]	earth	w, W	The actual character can not be a "w" or "W"

Step 2 - Complex regular expression examples

PHP regular expression tutorial

Now as you know the theory and basic syntax of PHP regular expressions it's time to create and analyze some more complex cases.

User name check with regular expression

First start with a user name check. In case of a registration form you may want to control available user names a bit. Let's suppose you don't want to allow any special character in the name except "_.-" and of course letters and numbers. Besides this you may want to control the length of the user name to be between 4 and 20.

First we need to define the available characters. This can be realised with the following code:

[a-zA-Z0-9_.-]

After that we need to limit the number of characters with the following code:

{4,20}

At least we need to put it together:

^[a-zA-Z-0-9_.-]{4,20}$

In case of Perl compatible regular expression surround it with '/'. At the end the PHP code looks like this:

Code:

1.  $pattern  = '/^[a-zA-Z0-9_.-]{4,20}$/';

2.  $username = "this.is.a-demo_-";

3.

4.  if (preg_match($pattern,$username)) echo "Match";

5.  else echo "Not match";

Email check with regular expression

At least let's see how we can check an email address with regular expressions. First take a careful look at the following example emails:

john.demo@demo.com
john@demo.us
john_123.demo_.name@demo.info

What we can see is that the @ is a mandatory element in an email. Besides this there must be some character before and some after it. More precisely there must be a valid domain name after the @.

So the first part must be a string with letters a numbers or some special characters like _-. In pattern we can write it as follows:

^[a-zA-Z0-9_.-]+

The domain name always have a let's say name and tld. The tld is the .com, .us. .info and the name can be any string with valid characters. It means that the domain pattern looks like this:

[a-zA-Z0-9-]+\.[a-zA-Z.]{2,4}$

Now we only need to put together the 2 parts with the @ and get the complete pattern:

^[a-zA-Z0-9._-]+@[a-zA-Z0-9-]+\.[a-zA-Z.]{2,5}$

The PHP code looks like this:

Code:

1.  $pattern = '/^[a-zA-Z0-9._-]+@[a-zA-Z0-9-]+\.[a-zA-Z.]{2,5}$/';

2.  $email   = "john123.demo_.name@demo.info";

3.

4.  if (preg_match($pattern,$email)) echo "Match";

5.  else echo "Not match";

Python function to create and print a list where the values are square of numbers

noreply@blogger.com (Unknown) — Sat, 01 Jan 2022 08:33:00 +0000

Python function to create and print a list where the values are square of numbers between 1 and 20

Method 1:-

def printValues():
    l = list()
    for i in range(1,21):
        l.append(i**2)
    print(l)
 
printValues()

output:-

[1, 4, 9, 16, 25, 36, 49, 64, 81, 100, 121, 144, 169, 196, 225, 256, 289, 324, 361, 400]
>>>

Method 2:-

sqrt = [elem**2 for elem in range(1,20)] 
print(sqrt)

output:-

[1, 4, 9, 16, 25, 36, 49, 64, 81, 100, 121, 144, 169, 196, 225, 256, 289, 324, 361]
>>>

Method 3:-

sqr_list = [] 
for i in range(1,20): 
  sqr_list.append(i*i) 
 
print(*sqr_list) 

output:-
1 4 9 16 25 36 49 64 81 100 121 144 169 196 225 256 289 324 361
>>>

tags:-
write a python function to create and print a list where the values are square of numbers

MySQL Alias

noreply@blogger.com (Unknown) — Sat, 01 Jan 2022 05:34:00 +0000

MYSQL: ALIASES

This MySQL tutorial explains how to use MySQL ALIASES (temporary names for columns or tables) with syntax and examples.

DESCRIPTION

MySQL ALIASES can be used to create a temporary name for columns or tables.

COLUMN ALIASES are used to make column headings in your result set easier to read.
TABLE ALIASES are used to shorten your SQL to make it easier to read or when you are performing a self join (ie: listing the same table more than once in the FROM clause).

Advantages of MySQL Aliases

Following are the advantage of an alias in MySQL:

It is preferred in the case when more than one table is going to use in a query.
It provides a very useful and flexible feature that allows us to achieve complex tasks quickly.
It makes the column or table name more readable.
It is useful when you use the function in the query.
It can also allow us to combines two or more columns.
It is also useful when the column names are big or not readable.

SYNTAX

The syntax to ALIAS A COLUMN in MySQL is:

column_name [ AS ] alias_name

The syntax to ALIAS A TABLE in MySQL is:

table_name [ AS ] alias_name

Parameters or Arguments

column_name

The original name of the column that you wish to alias.

table_name

The original name of the table that you wish to alias.

Optional. Most programmers will specify the AS keyword when aliasing a column name, but not when aliasing a table name. Whether you specify the AS keyword or not has no impact on the alias in MySQL. It is a personal choice in MySQL, unlike other databases. (Our examples will use AS when aliasing a column name but omit AS when aliasing a table name.)

alias_name

The temporary name to assign to the column or table.

Note:

If the alias_name contains spaces, you must enclose the alias_name in quotes.
It is acceptable to use spaces when you are aliasing a column name. However, it is not generally good practice to use spaces when you are aliasing a table name.
The alias_name is only valid within the scope of the SQL statement.

EXAMPLE - ALIAS A COLUMN

Generally, aliases are used to make the column headings in your result set easier to read. For example, when using the MAX function, you might alias the result of the MAX function in MySQL.

For example:

SELECT department, MAX(salary) AS highest

FROM employees

GROUP BY department;

In this example, we've aliased the MAX(salary) field as highest. As a result, highest will display as the heading for the second column when the result set is returned. Because our alias_name did not include any spaces, we are not required to enclose the alias_name in quotes.

However, it would have been perfectly acceptable to write this example using quotes as follows:

SELECT department, MAX(salary) AS "highest"

FROM employees

GROUP BY department;

Next, let's look at an example where we are required to enclose the alias_name in quotes.

For example:

SELECT department, MAX(salary) AS "highest salary"

FROM employees

GROUP BY department;

In this example, we've aliased the MAX(salary) field as "highest salary". Since there are spaces in this alias_name, "highest salary" must be enclosed in quotes.

EXAMPLE - ALIAS A TABLE

When you create an alias on a table, it is either because you plan to list the same table name more than once in the FROM clause (ie: self join), or you want to shorten the table name to make the SQL statement shorter and easier to read.

Let's look at an example of how to alias a table name in MySQL.

For example:

SELECT p.product_id, p.product_name, suppliers.supplier_name

FROM products p

INNER JOIN suppliers

ON p.supplier_id = suppliers.supplier_id

ORDER BY p.product_name ASC, suppliers.supplier_name DESC;

In this example, we've created an alias for the products table called p. Now within this SQL statement, we can refer to the products table as p.

When creating table aliases, it is not necessary to create aliases for all of the tables listed in the FROM clause. You can choose to create aliases on any or all of the tables.

For example, we could modify our example above and create an alias for the suppliers table as well.

SELECT p.product_id, p.product_name, s.supplier_name

FROM products p

INNER JOIN suppliers s

ON p.supplier_id = s.supplier_id

ORDER BY p.product_name ASC, s.supplier_name DESC;

Now we have an alias for suppliers table called s as well as the alias for the products table called p.

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JQuery Tutorial

jQuery Get Started

Downloading jQuery

Google CDN:

Microsoft CDN:

jQuery Syntax

The Document Ready Event

jQuery Selectors

The element Selector

The #id Selector

The .class Selector

More Examples of jQuery Selectors

Functions In a Separate File

jQuery Event Methods

What are Events?

jQuery Syntax For Event Methods

The on() Method

jQuery Effects

jQuery hide() , show() & toggle()

· Syntax:

$(selector).hide(speed,callback); $(selector).show(speed,callback);

$(selector).toggle(speed,callback);

· The optional speed parameter specifies the speed of the hiding/showing, and can take the following values: "slow", "fast", or milliseconds.

· Example:

$("#hide").click(function(){ $("p").hide(); }); $("#show").click(function(){ $("p").show(); });

$("button").click(function(){ $("p").toggle(); });

jQuery Fading Methods

· Syntax:

$(selector).fadeIn(speed,callback); $(selector).fadeOut(speed,callback);

· Example:

$("button").click(function(){ $("#div1").fadeIn(); $("#div2").fadeIn("slow"); $("#div3").fadeIn(3000); });

$("button").click(function(){ $("#div1").fadeOut(); $("#div2").fadeOut("slow"); $("#div3").fadeOut(3000); });

$("button").click(function(){ $("#div1").fadeToggle(); $("#div2").fadeToggle("slow"); $("#div3").fadeToggle(3000); });

$("button").click(function(){ $("#div1").fadeTo("slow", 0.15); $("#div2").fadeTo("slow", 0.4); $("#div3").fadeTo("slow", 0.7); });

jQuery Sliding Methods

· Syntax:

$(selector).slideDown(speed,callback); $(selector).slideUp(speed,callback);

· The optional speed parameter specifies the speed of the hiding/showing, and can take the following values: "slow", "fast", or milliseconds.

· The optional callback parameter is a function to be executed after the sliding completes.

· Example:

<html>

<head>

<script src="jquery-2.1.4.js"></script>

<script>

$(document).ready(function(){

$("#flip").click(function(){

$(selector).hide(speed,callback);
$(selector).show(speed,callback);

$("#hide").click(function(){
$("p").hide();
});

$("#show").click(function(){
$("p").show();
});

$("button").click(function(){
$("p").toggle();
});

$(selector).fadeIn(speed,callback);
$(selector).fadeOut(speed,callback);

$("button").click(function(){
$("#div1").fadeIn();
$("#div2").fadeIn("slow");
$("#div3").fadeIn(3000);
});

$("button").click(function(){
$("#div1").fadeOut();
$("#div2").fadeOut("slow");
$("#div3").fadeOut(3000);
});

$("button").click(function(){
$("#div1").fadeToggle();
$("#div2").fadeToggle("slow");
$("#div3").fadeToggle(3000);
});

$("button").click(function(){
$("#div1").fadeTo("slow", 0.15);
$("#div2").fadeTo("slow", 0.4);
$("#div3").fadeTo("slow", 0.7);
});

$(selector).slideDown(speed,callback);
$(selector).slideUp(speed,callback);