tag:blogger.com,1999:blog-20373737692493030332026-03-11T14:25:42.247+05:30Tech tips and explorationsRaviTejahttp://www.blogger.com/profile/12399360053821417293noreply@blogger.comBlogger343125tag:blogger.com,1999:blog-2037373769249303033.post-5761609506569385992023-09-27T08:23:00.019+05:302023-09-27T19:04:54.728+05:30

Context:Issue occurs when attempting to create a React app using below command in a custom directory where Node.js and npm are installed.npx create-react-app my-frontend-app --template typescriptPlatform: Windows 10Issue:Below errors occur when npm not being able to find the default directory due to the custom installation path.npm ERR! code ENOENT npm ERR! syscall lstat npm ERR!

RaviTejahttp://www.blogger.com/profile/12399360053821417293noreply@blogger.com0tag:blogger.com,1999:blog-2037373769249303033.post-39049532453899950352023-05-30T23:30:00.002+05:302023-05-31T21:51:38.018+05:30

The solution is same as LC's official editorial Approach 2: Array, Optimized SpaceBelow is my explanation in detailed manner.The problem statement asks for finding the number of days you have to wait until a warmer temperature, given a list of daily temperatures.Here's how the code work without using monotonic stack: Initialize variables: `n` represents the length of the input list `

RaviTejahttp://www.blogger.com/profile/12399360053821417293noreply@blogger.com0tag:blogger.com,1999:blog-2037373769249303033.post-58770841593325718302023-05-28T22:38:00.008+05:302023-05-29T11:35:15.316+05:30

P𝗋𝗈𝖻𝗅𝖾𝗆 S𝗈𝗅𝗏𝗂𝗇𝗀 Tips 1. If an input array is sorted then a. Binary search O(log n) b. Two pointers O(n) 2. If asked for all permutations/subsets then a. Backtracking (First preference) b. Breadth First Search. 3. If given a tree or graphs then a. DFS  (Preorder, Inorder, Postorder): O(n) b. BFS (Level Order): O(n) 4. If Binary search tree: a. - Left < Cur < Right: O

RaviTejahttp://www.blogger.com/profile/12399360053821417293noreply@blogger.com0tag:blogger.com,1999:blog-2037373769249303033.post-62424380621318826842023-05-28T22:07:00.004+05:302023-05-28T22:07:48.600+05:30

Problem    : https://leetcode.com/problems/valid-sudoku/Solution    : https://leetcode.com/problems/valid-sudoku/solutions/3572587/92ms-beats-92-52-python-36-valid-sudoku-28-may-2023/Submisson    : https://leetcode.com/problems/valid-sudoku/submissions/Github code    :    https://github.com/ravivanjarapu/

RaviTejahttp://www.blogger.com/profile/12399360053821417293noreply@blogger.com0tag:blogger.com,1999:blog-2037373769249303033.post-47365260602141710442023-05-28T21:27:00.008+05:302023-05-28T21:34:36.883+05:30

Problem link: https://leetcode.com/problems/product-of-array-except-self/Description (copied from above link)Given an integer array nums, return an array answer such that answer[i] is equal to the product of all the elements of nums except nums[i].The product of any prefix or suffix of nums is guaranteed to fit in a 32-bit

RaviTejahttp://www.blogger.com/profile/12399360053821417293noreply@blogger.com0tag:blogger.com,1999:blog-2037373769249303033.post-2702640292188614812022-12-04T11:49:00.003+05:302022-12-04T12:17:06.264+05:30

Newton-Raphson methodIf you enjoyed this post, make sure you subscribe to my RSS feed! Comments are encouraged

RaviTejahttp://www.blogger.com/profile/12399360053821417293noreply@blogger.com0tag:blogger.com,1999:blog-2037373769249303033.post-61414924868250490132022-12-04T11:30:00.001+05:302022-12-04T11:30:48.636+05:30

Example1: f(x) = x4 + 2x3 - x2 + 4x -1  Answer: f1(x) = 4x3 + 6x2 - 2x + 4  Reference: https://www.youtube.com/watch?v=QqF3i1pnyzUIf you enjoyed this post, make sure you subscribe to my RSS feed! Comments are encouraged

RaviTejahttp://www.blogger.com/profile/12399360053821417293noreply@blogger.com0tag:blogger.com,1999:blog-2037373769249303033.post-31678405828119075872017-12-09T11:40:00.001+05:302017-12-09T11:40:11.645+05:30

Below is for Ubuntu. source djangoTestEnv/bin/activate cd Desktop django-admin startproject blogSite cd blogSite python manage.py startapp myBlog Go to blogSite/blogSite/settings.py and add 'myBlog' in INSTALLED_APPS section. It should look similar to belowINSTALLED_APPS = [    'django.contrib.admin',    'django.contrib.auth',    'django.contrib.contenttypes',

RaviTejahttp://www.blogger.com/profile/12399360053821417293noreply@blogger.com0tag:blogger.com,1999:blog-2037373769249303033.post-31878344632342548292017-12-01T22:28:00.002+05:302017-12-02T10:49:59.895+05:30

Field Types: Numeric Data IntegerField  DecimalField Textual Data CharField Requires max_length attribute TextField Doesn't require max_length attribute EmailField URLField File Data FileField Example: filename.docx ImageField Example: abc.jpg Miscellaneous Data BooleanField DateTimeField This link provides detailed info about field arguments and field types.

RaviTejahttp://www.blogger.com/profile/12399360053821417293noreply@blogger.com0tag:blogger.com,1999:blog-2037373769249303033.post-32823620977545530952017-12-01T22:01:00.000+05:302017-12-02T10:50:21.691+05:30

settings.py is global to all apps in a django project. Django documentation in this link provides good overview of the settings. This link provides more detailed info of these settings Settings those needed change for first time. INSTALLED_APPS TEMPLATES STATICFILES_DIRS Settings those might needed change. DEBUG Set to true by default, but is best set to false

RaviTejahttp://www.blogger.com/profile/12399360053821417293noreply@blogger.com0tag:blogger.com,1999:blog-2037373769249303033.post-53606470991129199532017-11-30T23:38:00.002+05:302017-12-01T22:01:53.911+05:30

cd Desktop/DjangoPractice/firstdjango python manage.py startapp firstapp Files inside firstapp folder are below models.py -- DB interaction admin.py -- admin interface views.py -- App's logic and URL request / response tests.py -- Automated tests  migrations folder -- auto generated. Migration files about DB tables changes for the app Previous in this Series | Next

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source djangoTestEnv/bin/activate Create a folder like DjangoPractice on Desktop cd Desktop/DjangoPractice django-admin startproject firstdjango Auto creates  a folder named firstdjango and required files in it Subfolder named firstdjango inside firstdjango will have  init.py settings.py Configures Django urls.py Routes requests based on URL wsgi.py

RaviTejahttp://www.blogger.com/profile/12399360053821417293noreply@blogger.com0tag:blogger.com,1999:blog-2037373769249303033.post-27734857835958220612017-11-30T22:42:00.003+05:302017-12-01T21:47:36.317+05:30

On Ubuntu Machine, use below steps. sudo -H pip install virtualenv Using pip and installing virtualenv (recommended) instead of global installation virtualenv -p python djangoTestEnv djangoTestEnv is sample name of virtual environment source djangoTestEnv/bin/activate Activating djangoTestEnv pip install django Installing django in djangoTestEnv pip freeze This is to check

RaviTejahttp://www.blogger.com/profile/12399360053821417293noreply@blogger.com0tag:blogger.com,1999:blog-2037373769249303033.post-66176058130145280472017-09-18T23:45:00.002+05:302017-09-18T23:45:55.601+05:30

Assuming input.ui is the file created in Qt Designer, output.py is the python code file name, open Terminal and cd to input.ui folder. Type pyuic4 -x input.ui -o output.py and hit Enter output.py gets created in same folder and run it from Python to get the UI window. If you enjoyed this post, make sure you subscribe to my RSS feed! Comments are encouraged

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For Ubuntu: Below is the command to install PyQt4 and Qt Designer for Python 2 sudo apt-get install pyqt4-dev-tools qt4-designer If you enjoyed this post, make sure you subscribe to my RSS feed! Comments are encouraged

RaviTejahttp://www.blogger.com/profile/12399360053821417293noreply@blogger.com0tag:blogger.com,1999:blog-2037373769249303033.post-43813809510424619272016-06-01T12:56:00.000+05:302016-06-01T12:56:06.742+05:30

ERROR: ~/.buildozer/android/platform/android-sdk-XX/tools/ant/build.xml:taskdef A class needed by class com.android.ant.GetUiTargetTask cannot be found: com/android/utils/ILogger Context: Running ant debug for buildozer SOLUTION: Back up the Lib folder in /usr/share/ant (check by using whereis ant) of original ant installation. Make a link of ~/.buildozer/android/platform/

RaviTejahttp://www.blogger.com/profile/12399360053821417293noreply@blogger.com0tag:blogger.com,1999:blog-2037373769249303033.post-35894650403482460662016-05-31T19:47:00.001+05:302016-05-31T19:48:23.725+05:30

Assuming, $ANDROID_HOME (environmental variable ) refers to android sdk directory, you can inject the ANDROID_HOME  into the sdk.dir property using the following ant command. $ ant debug -Dsdk.dir=$ANDROID_HOME ANDROID_HOME must be an absolute path such as /home/username/something/android-sdk If you enjoyed this post, make sure you subscribe to my RSS feed! Comments are encouraged

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SOLUTION: sudo modprobe -r psmouse sudo modprobe psmouse If you enjoyed this post, make sure you subscribe to my RSS feed! Comments are encouraged

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Context: Running android update project ERROR: command not found Solution: export ANDROID_HOME=/Applications/android-sdks Add Tools to PATH export PATH=${PATH}:${ANDROID_HOME}/tools Add platform-tools to PATH export PATH=${PATH}:${ANDROID_HOME}/platform-tools If you enjoyed this post, make sure you subscribe to my RSS feed! Comments are encouraged

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Context: Running buildozer android debug ERROR: subprocess.CalledProcessError: Command '['ant', 'debug']' returned non-zero exit status 1 SOLUTION: Go to ~/.buildozer/android/platform/android-sdk-24/tools/ant Run ant debug You will find issues. Sort them out. If you enjoyed this post, make sure you subscribe to my RSS feed! Comments are encouraged

RaviTejahttp://www.blogger.com/profile/12399360053821417293noreply@blogger.com0tag:blogger.com,1999:blog-2037373769249303033.post-1642841150756946872016-05-30T18:53:00.001+05:302016-05-30T18:53:13.173+05:30

ERROR: Target id 'android-xx' is not valid. Use 'android list targets' to get the target ids. ... ... ... File "/usr/lib/python2.7/subprocess.py", line 541, in check_call     raise CalledProcessError(retcode, cmd) subprocess.CalledProcessError: Command '['ant', 'debug']' returned non-zero exit status 1 SOLUTION: Upgrade ant that is linked to Buildozer Install using sudo apt-get

RaviTejahttp://www.blogger.com/profile/12399360053821417293noreply@blogger.com0tag:blogger.com,1999:blog-2037373769249303033.post-10904724261426786252016-05-30T18:43:00.003+05:302017-09-18T22:42:35.418+05:30

Type which ant in terminal.  Mine resulted with /usr/bin/ant. If apache ant is not installed already, you might get an error. Uncomment #android.ant_path = line in buildozer.spec use android.ant_path = /usr/bin/ant  Now you can control the upgrades of ant and get it updated in buildozer automatically. Otherwise, there will be two instances (can be two different

RaviTejahttp://www.blogger.com/profile/12399360053821417293noreply@blogger.com0tag:blogger.com,1999:blog-2037373769249303033.post-89790162192228705692016-05-30T16:17:00.001+05:302016-05-30T16:17:40.482+05:30

I am trying to build apk using buildozer and below is the error I've encountered: ant/build.xml :  Unable to resolve project target 'android-19 ... ... ... Traceback (most recent call last):   File "build.py", line 517, in <module>     make_package(args)   File "build.py", line 365, in make_package     subprocess.check_call([ANT, arg])   File "/usr

RaviTejahttp://www.blogger.com/profile/12399360053821417293noreply@blogger.com0tag:blogger.com,1999:blog-2037373769249303033.post-41236886308193641022016-05-30T14:43:00.003+05:302016-05-30T14:46:03.692+05:30

ERROR: # Check that aidl can be executed # build-tools folder not found /home/raviteja/.buildozer/android/platform/android-sdk-24/build-tools # Search for Aidl # Aidl not found, please install it. SOLUTION: Above error says build-tools folder is not found. I checked in my /home/raviteja/.buildozer/android/platform/android-sdk-24/ and build tools folder is not available really. Launched

RaviTejahttp://www.blogger.com/profile/12399360053821417293noreply@blogger.com0tag:blogger.com,1999:blog-2037373769249303033.post-4103903129826176222016-05-30T08:24:00.002+05:302016-05-30T08:24:28.250+05:30

gksudo nautilus Navigate via nautilus to: /var/lib/dpkg/info Search for: package name .. "openjdk-9-jdk" in my case Delete them. close nautilus sudo apt-get update If you enjoyed this post, make sure you subscribe to my RSS feed! Comments are encouraged

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