KKREDDYS

Dates & Time - Using Pandas Library

2020-05-29T18:57:00.003+01:00

Lets see some of methods to deal with dates and time data types using pandas:

Merging, Joining & Concat of Dataframes using Pandas Library

2020-05-27T22:35:00.004+01:00

Some of the methods to Join, Merge & Concat DataFrames using Pandas Library:

GroupBy & Aggregations using Pandas

2020-05-27T22:33:00.003+01:00

Lets see some of the methods to aggregate data using pandas library:

MultiIndex in Pandas DataFrame

2020-05-25T22:24:00.003+01:00

Working with Text data using Pandas

2020-05-25T22:22:00.003+01:00

Lets see some of methods to work on string columns using Pandas library:

Selection, Filtering & Renaming - Pandas Dataframe

2020-05-24T17:16:00.001+01:00

Some of the methods to Select/Filter/rename on columns/rows:

Continuation on Pandas Data frame

2020-05-24T17:12:00.002+01:00

lets see some of methods to get familiar with Padas Dataframe:

Introduction to Pandas Dataframe

2020-05-19T22:45:00.005+01:00

Pandas Dataframe and some of its methods:

Let me know your comments on this!!

Introduction to PANDAS, JUPYTER NOTEBOOK & Series

2020-05-17T23:09:00.007+01:00

Lets start introduction to Anaconda prompt by looking into below commands which will help in creating environments, installing libraries etc.

Here are some of shortcuts in jupyter notebook:

Lets start with pandas series with various methods and its uses:

Ratio proportion variation-3

2013-08-17T18:14:00.001+01:00

Special calculations-1

2013-08-17T18:10:00.005+01:00

Multiplying numbers shortcuts -1

2013-08-17T18:10:00.003+01:00

Numbers-2 shortcuts

2013-08-17T18:10:00.001+01:00

Multiplying numbers shortcuts -2

2013-08-17T17:59:00.001+01:00

Numbers-1 shortcuts

2013-08-17T17:57:00.001+01:00

Ratio proportion variation-2

2013-08-17T17:53:00.001+01:00

Ratio proportion variation-1 shortcuts

2013-08-17T17:50:00.001+01:00

Hi...
Find the image

How to unhide files in a folder

2012-12-23T14:19:00.000+00:00

Enter into command prompt by clicking into Accessories->Command Prompt
Enter into select drive by typing the drive letter:
Then type "attrib -a -s -h -r /s /d /l" without semicolon.
Your problem is solved

How to find the IP or MAC address of a computer

2012-11-27T03:28:00.002+00:00

Every computer has unique IP and MAC address. So let us know how to find the IP and MAC address of a computer.........

In Windows XP

Click on start
Click on run
Type cmd
Type ipconfig/all
IPv4 address gives the IP address of your computer
Physical address gives the MAC address of your computer

In Windows Vista/7/8

Click on start
Go to all programs
Click on accessories
Click on Command Prompt
Type ipconfig/all
IPv4 address gives the IP address of your computer
Physical address gives the MAC address of your computer

c programs asked in interviews

2012-10-31T05:29:00.000+00:00

Recently I have goggled about programs asked in interview....and I found this website where both questions and answers were given

for c programs asked in interviews

there are several sites 1) click here
2) click here

For complete details on C visit here

How resistive Touch Screen Works??

2012-10-27T14:09:00.000+01:00

A touch screen is an electronic visual display that can detect presence and location of touch within the display area...

It is a two dimensional sensing device that is made of two sheets of material separated by small spacers. There are three main touch screen technologies viz., resistive, capacitive and surface acoustic wave. Here i will discuss about resistive touch screen

Resistive touch screen:

The resistive touch screen consists of flexible top layer made of polythene and rigid bottom layer made of glass. Both the layers are spaced with spacers and are coated with indium tin oxide. When the screen is operating a small current flows in between the space. When a touch is made, the flexible screen presses down to touch the glass layer. A change in current is hence detected and coordinates of the point of touch calculated by the controller and parsed into readable signal for the operating system to react accordingly.

The four-wire resistive touch screen uses both the layers to calculate the axes information of the touch. Touch measurement is a two-step process. The x-coordinate of the touch point is calculated by creating a voltage gradient on flexible layer, and the y-coordinate is determined by creating a voltage gradient along the bottom layer.

Shortcuts in solving aptitude-10

2012-10-17T03:34:00.001+01:00

SIMPLE INTEREST COMPOUND INTEREST

Interest

Interest is the ‘extra’ money paid by the borrower to the lender for using the money for a specified

period of time.

Principal (P) : - The money lent or borrowed is called the Principal.

Amount (A) : - The total money, i.e. Principal + Interest is called the amount.

Rate of interest (r) :- The rate at which interest is calculated on the Principal is called the rate of interest.

Interest is of two kinds

1. Simple interest (I)

If the interest is calculated for every time period (generally calculated yearly, half-yearly, quarter-yearly) only on the original sum (Principal) borrowed, then such interest is called as the simple interest.

The interest is same for each qf the time-periods.

i.e. if the interest for one time-period (if taken as a year) is I, then the interest for ‘n’ time-periods(years) is ‘nI’

2. Compound interest

In this method, at the end of each time period, the interest is added to the principal, and this amount becomes the new Principal for/the next time period. The amount at the end of the second time period becomes the Principal for the third time period and so on.

The interest is not same for all the time-periods, but the interest for any time period is greater than the interest for the preceeding time-period. Compound interest (CI) = Final amount - initial principal

To Exercise some more problems on SI and CI visit here

Shortcuts in solving aptitude-9

2012-10-17T03:31:00.003+01:00

NUMBERS

Natural numbers

The set of counting numbers 1, 2, 3, 4, …………are called as the natural numbers, denoted by N.

N = {1, 2, 3, ...}

Whole numbers

The set of natural numbers together with the number ‘0’ is known as the set of whole numbers, denoted by W.

W= {0, 1,2,3, ...)

Integers

The negative whole numbers, the number '0' and the natural numbers together form the set of Integers, denoted by Z.

Z= {... -3, -2,– 1, 0, 1.2.3, …..}

Rational numbers

Numbers which can be written in the form p/q where p and q are integers and q ≠0 are called as rational numbers, denoted by Q.

Decimal representation of rational numbers

v If a fraction (rational number) in its lowest terms has no other prime factors except 2 and 5. we get a terminating decimal.

Irrational numbers

The numbers, which cannot be expressed as rational numbers is called as an irrational number.

Note:

Every non-terminating, non-recurring decimal is an irrational number.

Note :

A number may he a rational number or an irrational number, but! it cannot be both.

Real numbers

The set of all numbers comprising rational numbers and irrational numbers is known as the set of real numbers, denoted by R.

Note :

v On the number line, there is a point corresponding to every real number and to every point on the number line, there is a real number. Hence the number line is called the Real Number line.

v Real numbers are so called because they can be seen as points representing them on the number line.

Complex numbers

There is no real number, whose square is a negative number.

E.g. is not a real number.

Such numbers are called as imaginary numbers.

The set of numbers comprising of real numbers and imaginary numbers is known as the set of complex numbers, denoted by C.

The ordered pair (a, b) where a and b are real numbers, when expressed in the form a + ib, is called a complex number.

a is called the real part, and b is called the imaginary part.

Note:

v Every real number a can be represented as a complex number, (a, 0).

v The complex numbers a + ib and a - ib are called conjugate complex numbers. Each is called the conjugate of the other.

v The sum and product of two conjugate complex numbers are real.

v Every complex number can be represented as a point in the coordinate plane, by taking real part on the x-axis and the imaginary part on the y-axis.

Hence, x axis is called real axis

y-axis called imaginary axis.

Some of Mathematical formula are unable to mention here...so for more visit here

Shortcuts in solving aptitude-8

2012-10-17T03:26:00.001+01:00

Permutations and Combinations

Formulae:

Factorial Notation:

Let n be positive integer. Then ,factorial n denoted by n!

is defined as n! = n(n-1)(n-2). . . . . . . .3.2.1

Permutations:

The different arrangements of a given number of things by

taking some or all at a time, are called permutations.

e.g.:- All permutations( or arrangements)made with the letters

a,b,c by taking two at a time are (ab,ba,ac,ca,bc,cb)

Numbers of permutations:

Number of all permutations of n things, taken r at a time is

given by nPr = n(n-1)(n-2). . .. . . (n-r+1)

= n! / (n-r)!

An Important Result:

If there are n objects of which p1 are alike of one kind;

p2 are alike of another kind ; p3 are alike of third kind and

so on and pr are alike of rth kind, such that

(p1+p2+. . . . . . . . pr) = n

Then, number of permutations of these n objects is:

n! / (p1!).(p2!). . . . .(pr!)

Combinations:

Each of different groups or selections which can be formed by

taking some or all of a number of objects, is called a combination.

e.g.:- Suppose we want to select two out of three boys A,B,C .

then ,possible selection are AB,BC & CA.

Note that AB and BA represent the same selection.

Number of Combination:

The number of all combination of n things taken r at a time is:

nCr = n! / (r!)(n-r)!

= n(n-1)(n-2). . . . . . . tor factors / r!

Note: nCn = 1 and nC0 =1

An Important Result:

nCr = nC(n-r)

To exercise problems regarding permutations & combinations visit here

Probability

Introduction:

Experiment:

An operation which can produce some well-defined outcome is called an experiment.

Random Experiment:

An experiment in which all possible out comes are known and the exact output cannot be predicted in advance is called a random experiment. EX:

1) Rolling an unbiased dice.

2) Tossing a fair coin.

3) Drawing a card from a pack of well-shuffled cards .

4)Picking up a ball of certain color from a bag containing balls of different colors.

Details:

1) When we thrown a coin ,then either a Head(H) or a Tail(T)appears.

2)A dice is a solid cube ,having 6 faces, marked 1,2,3,4,5,6respectively. When we throw a die ,the outcome is the number that appears on its upper face.

3)A pack of cards has 52 cards.

It has 13 cards of each suit, namely spades, clubs, hearts and diamonds.

Cards of spades and clubs are black cards.

Cards of hearts and diamonds are red cards.

There are four honors of each suit.

These are Aces, Kings, queens and Jacks.

These are called Face cards.

Sample Space:

When we perform an experiment ,then the set of S of all possible outcomes is called the Sample space .

Event: Any subset of a sample space is called an Event.

Probability of occurrence of an Event:

Let S be the sample space.

Let E be the Event.

Then E c S i.e. E is subset of S then

probability of E p(E) =n(E)/n(S).

Results on Probability:

1)P(S) =1.

2)0 < P(E) < 1

probability of an event lies between 0 and 1.

Max value of probability of an event is one.

3)For any events A and B we have .

P(AUB) =P(A) +P(B) -P(A n B ).

4)If A denotes (not -A) then

P (A) =1-P(A)

P(A)+P(A) =1.

To Exercise problems in probability visit here

Shortcuts in solving aptitude-7

2012-10-16T18:11:00.001+01:00

Allegation or Mixtures

Important Facts and Formulae:

1. Allegation: It is the rule that enables us to find the Ratio in which two of more ingredients at the given price must be mixed to produce a mixture of a desired price.

2. Mean Price: The cost price of a unit quantity of the mixture is called the mean price.

3. Rule of Allegation: If two ingredients are mixed then

Quantity of Cheaper / Quantity of Dearer = (C.P of Dearer – Mean Price) /(Mean Price–C.P of Cheaper).

C.P of a unit quantity of cheaper(c) C.P of unit quantity of dearer (d)

Mean Price (m)

(d-m) (m-c)

Cheaper quantity: Dearer quantity = (d-m):(m-c)

4. Suppose a container contains x units of liquid from which units are taken out and replaced by water. After n Operatations the quantity of pure liquid = x (1 – y/x)n units.

To exercise some problems on allegation or mixtures visit here

Boats and Streams

Important facts:

1)In water, the direction along the stream is called downstream.

2)Direction against the stream is called upstream.

3)The speed of boat in still water is U km/hr and the speed of

stream is V km/hr then

speed downstream =U + V km/hr

speed up stream = U – V km/hr

Formulae:

If the speed downstream is A km/hr and the speed up stream is

B km/hr then speed in still water = ½(A+B) km/hr

rate of stream =1/2(A-B) km/hr

To exercise some problems on Boats and streams visit here