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Activate virtual environment and install requirements in the first setup automatically - Python, Windows

I want to write a first_setup.py script, where users can run it for the first time and the script will do the entire setup automatically, namely it will create a virtual environment, activate it, and install the requirements with pip. Users can then start to use the program without worrying about any dependency issue.
Therefore, I used venv together with subprocess library. My Python version is 3.7.5. With the following command, it creates the virtual environment in the working directory:
env_name = ".venv"
subprocess.run(["python", "-m", "venv", env_name])
However, activation doesn't work. I tried to activate it in various ways, for example:
subprocess.run([f"{venv_name}\\Scripts\\Activate.ps1"], shell=True)
This just opens Activate.ps1 in Windows Text Editor like a .txt file (?). I also thought to add .../Scripts/python.exe to the PATH variable, but it didn't work actually.
Furthermore, when the venv created by the script, VS Code pops up a message saying a venv detected, do you want to use it? If I click on Yes, then it changes my interpreter to venv, which is exactly what I want to do, but automatically with the first_setup.py script.
How can I proceed?

Does this first_setup script need to be Python?
The problem is that the activate script sets environment variables for the shell, which is why it’s usually run with ‘source’.

try using bash file:
python3 -m venv venv
source venv/bin/activate
pip install your_library

How to use a Virtual Environment?

I am using Python 3.7.9 Shell.
I created a virtual environment in this location
C:\Users\my_username\Desktop\Projects.venv
Inside of Python Shell, when I type: import numpy, which is in my .venv\lib folder, it says that the module does not exist.
Using Python Shell, how do I make use of the contents in .venv? In particular, the libraries located there?
Edit #1: Include Details
In my windows command line, it has (.venv) off to the left.
I have run the Activate file. I then started Python.
In my \lib\site-packages area, I have the requests library.
When I open up Python Shell and type "import requests", it says "no such library can be found"
I am using Windows 10
I installed the libraries while in the (.venv) environment.
Theory:
In the virtual environment, in Python Shell, it's searching a different location for libraries...now if I can just figure out where it's searching and how to change that...I might be able to make progress.
Edit #2: My Progress
My theory was correct. Despite using a virtual environment, it's not looking for the libraries installed in (.venv)\lib\site-packages, it's looking somewhere outside of that.
Now I just need to figure out how to make the Python code look for libraries inside of (.venv)\lib\site-packages when I'm in the virtual environment.
When I run the python.exe file inside of the (.venv)\Scripts location, it recognizes the virtual environment scripts.
If I click on my version of Python.Exe located in my C:...\Programs\Python 3.7 folder, it doesn't recognize them.
I was under the impression it didn't matter where I clicked on the Python.exe file if I did it after going to the virtual environment in the command line? Is this not true?
Edit #3: Important Links
Where Python Looks for Modules When Importing

Right from the official docs https://docs.python.org/3/tutorial/venv.html#creating-virtual-environments
Once you’ve created a virtual environment, you may activate it.
On Windows, run:
tutorial-env\Scripts\activate.bat
On Unix or MacOS, run:
source tutorial-env/bin/activate
this is done in your shell before starting python at its prompt, and allows you to choose different python versions in addition to other benefits

zsh: commands not working for pip, conda, python

So here is my story:
As we know macos comes with pyhton 2.7 preinstalled. Years ago, I installed python 3.7.0 and all going good. I started working with Tensorflow and during that time tensorflow wasn't compatible with 3.7.0 so switch the version to 3.6.6 somehow :). After some time i installed anaconda and it installed 3.7.3.
At this point:
When i open my python IDLE shell, it runs on 3.6.6
anaconda Jupiter notebook shows 3.7.3.
Then i learned to create virtual environments through terminal and i use following code to create virtual environment:
pip install virtualenv
virtualenv project_env
And after i activate the virtual environment the python version it shows is 3.7.3.
Then recently i changed the terminal shell to zsh and now everything is kind of messed up. I'm
Terminal can't find conda commands. How to fix that?
Now i can't create virtual environment through virtualenv project_env. It says command not found. Why? It use to create virtual environments with python 3.7.3.
Now to create virtual environment i use python3 -m venv project_env this creates the virtual environment with python 3.6.6. If i use python3.7 -m venv project_env it creates environment with python 3.7.0.
I can't find a way to create virtual environments with python 3.7.3.
I need help with above troubles caused after installing zsh and help with accessing python versions wherever i need. How do i update python version 3.7.0 to latest or any specific version like 3.7.3. Hows python 3.8.4 to use, i mean like i had trouble importing tensorflow in python 3.7.0.
I hope you will understand my trouble and searched a lot for solutions. I'm so confused right now, couldn't even figure out the title of my problem.

Based on the fact your shell can't find conda now, you should look at your "path" environment variable. Whenever you change from one shell to another, you need to look at and possible create or modify the files the shell uses upon startup. These files setup your environment (PATH, PYTHONPATH, etc), create aliases, etc. You may need to create the .zshrc, .zprofile, .zlogin etc files and add the same settings as your previous shell's startup files.
Example:
If you used the bash shell previously you would need to modify the .zshrc file to include your settings in the .bashrc file. Syntax may be different, so a straight copy may or may not work.
Try this as a quick temporary fix (may or may not work, depending on your current ~/.profile settings:
Create a ~/.zprofile file with this code inside:
emulate sh
. ~/.profile
emulate zsh
references:
https://superuser.com/questions/187639/zsh-not-hitting-profile
http://zsh.sourceforge.net/Intro/intro_3.html

Stuck when setting up to use anaconda with VS Code and Integrated Git terminal

I want to learn Data Science and so have used some really popular Python modules likes Pandas, Matplotlib, Numpy, etc. So I clean installed Anaconda and am now using it as my default Python interpreter and also using Conda for installing packages and making virtual environments. I use VS Code as my daily text editor. But I have run into some issues when using the integrated Git terminal in VS Code with the Anaconda Python interpreter.
There are a couple of issues that I am facing. One of the first issues that I see is when I am using CMD to run Python. If I type and enter python in cmd, the Python interpreter provided by anaconda comes up. But I also get a warning:
Warning:
This Python interpreter is in a conda environment, but the environment has not been activated. Libraries may fail to load. To activate this environment please see https://conda.io/activation
I didn't expect to get this output. Anyway, there's another problem in VS code. But first I would like to mention that I have checked "Add to PATH" when installing Anaconda so no issues there. Now, when I open a new Terminal in VS Code, automatically C:/Users/User/Anaconda3/Scripts/activate is run and then conda activate base is run. But when conda activate base is run, automatically, as mentioned, I get a CommandNotFoundError. It states Your shell has not been properly configured to use 'conda activate'.
If using 'conda activate' from a batch script, change your
invocation to 'CALL conda.bat activate'
And then I am told to initialize my shell, so I did conda init bash but still no luck. And this brings me to talk about .bash_profile. I think it has to do something with this bash profile. Anyway, this is what is in my bash profile
# >>> conda initialize >>>
# !! Contents within this block are managed by 'conda init' !!
eval "$('/C/Users/User/Anaconda3/Scripts/conda.exe' 'shell.bash' 'hook')"
# <<< conda initialize <<<
Just a summary of the problem:
Unexpected warning in CMD when running Anaconda Python interpreter
Automatically run Anaconda Scripts and conda activate base when opening new Terminal in VS Code
Conda init bash not helping
P.S I have tried using conda activate [env_name] in CMD and also in Git Bash and they work without any issues. In other words, Anaconda and Conda work perfectly outside of VS Code terminal.

I have figured out the answer myself and would like to share it here. First of all at the time of writing the question I was using Git Bash as my Terminal in VS Code (am still using it). So the issue was that when I ran the command conda init bash in Git Bash or the VS Code Terminal, Conda just basically put the command used for activating Conda environments in the .bash_profile since it is sourced during logging into Bash. But the integrated Terminal in VS Code is a subshell of a Git Bash session. That is why .bash_profile is NOT sourced in VS Code since .bash_profile is only sourced during the main Bash session. The .bashrc file is the file that is sourced when creating a Terminal session in VS Code. So what you actually need to do is take the code that is put into .bash_profile by conda init bash and paste it into your .bashrc file and make the .bash_profile source that .bashrc file automatically.
So, to sum up, using conda init bash will put the conda command in the .bash_profile and it is usually sourced by Git Bash, but VS Code Git Bash terminal will use .bashrc.
So you can just cut and paste the code from .bash_profile to .bashrc (as already mentioned) or if you want, just simply follow this: put this code in your .bash_profile:
if [ -f ~/.bashrc ]; then
source ~/.bashrc
fi
And in your .bashrc, put this code:
# >>> conda initialize >>>
# !! Contents within this block are managed by 'conda init' !!
eval "$('{path_to_your_conda.exe}' 'shell.bash' 'hook')"
# <<< conda initialize <<<
# You can get conda.exe path by using `which conda` in Git Bash
Now, when you open up a Git Bash session in VS Code Terminal, you can use conda activate env_name to activate any environments you have.
Everything is now supposed to work as expected in VS Code terminal but I would like to further elaborate about something. If you want, you can skip the conda init bash process (NOT recommended, just read on for additional knowledge but please follow the above steps only). This is a feature that was introduced in conda 4.4.0. Till then the way of activating conda environments was by using source activate but that command was NOT cross-platform, meaning that the command could not be used in OSes like Windows.
So they made this change by introducing commands like: conda activate env_name so that conda environments become much easier to use despite the OS platform.
conda activate also has other advantages. This is directly from their release docs:
conda activate: The logic and mechanisms underlying environment activation have been reworked. With conda 4.4, conda activate and conda deactivate are now the preferred commands for activating and deactivating environments. You'll find they are much more snappy than the source activate and source deactivate commands from previous conda versions. The conda activate command also has advantages of (1) being universal across all OSes, shells, and platforms, and (2) not having path collisions with scripts from other packages like Python virtualenv's activate script.
I used this question as a reference. Check it out to learn more.
Having said that, using source activate env_name will still work if you are using Git Bash, even in VS Code Git Bash terminal. source activate env_name requires no prior set up or config. But it is highly recommended that you only use conda init to set everything up and then use conda activate env_name.
[NOTE]: Locating and modifying the said .bashrc and .bash_profile on Windows is usually not as simple as it is on Linux. But can be done fairly easily like this:
It goes without saying but, you should have Git Bash installed. Having Git Bash installed should, as far as I know, automatically create .bashrc or .bash_profile or maybe both. These files are called "dotfiles" (since they start with a dot) and these are by default hidden on most OSes and definitely on Windows. If they were auto-created by Git Bash on your system, it is most likely that they are placed in your home directory. Home directory on Windows is C:\Users\<you>\. With that said, follow this:
Open Git Bash and go to your home directory with: cd. Just type this and you will be in your home directory
Enter this command: ls -a and you will see all your files, even hidden ones. Look for .bash_profile and .bashrc. Both should be present. If they are, you are ready to follow the above instructions. But if one is not there or if both are missing create them using: touch .bashrc && touch .bash_profile. You should now see these files when you again type: ls -a
That's it. Now that you have your .bashrc and .bash_profile, you can follow the above instructions. Also, to access these two files quicker, open them like this with VS Code: code ~/.bashrc or code ~/.bash_profile. Now, modify these two files as per the instructions.
In the question, I have also talked about VS Code activating Conda environments automatically. There's no issue with VS Code doing that since this is the default behavior.
I misinterpreted that as something that's an issue. But if anyone was looking to stop VS Code from automatically doing that, I would recommend trying to set this in the user settings:
"python.terminal.activateEnvironment": false

EDIT: A better solution than using source activate to get conda activate commands to work in the git bash terminal in VS Code:
Run conda init in the Git Bash Terminal in VS Code
Type in bash -l in VS Code's Git Bash terminal to launch your configured shell as a login shell
You should now be able to run conda activate commands per normal!
More info: bash -l runs your ~/.profile/~/.bash_profile/~/.zprofile scripts where the conda executable is actually referenced (but in which Git Bash as a integrated terminal does not run by default and refers to). Hence, git bash does not know where to search for conda when running conda activate commands and per Arafat's explanation above, running conda init changes the git bash PATHs in this .bash_profile file, but is ineffectual as the git bash terminal in VS Code doesn't actually refer to this file! Further info in VS Code's official docs.
Supplementing the explanation of the accepted answer, I've posted a solution that worked for me here that might possibly help others (changing user settings did not solve the issue for me). Link could also point to other working solutions if the below or accepted answer above doesn't work.
NOTE: Please read Arafat's answer before attempting the source activate method below to understand why it's not normally recommended. That said leaving it up as it still solves the problem.
Here's what worked for me using the Git Bash terminal in VS Code on
windows in succinct steps:
source activate env-name - You should see your line appended by the (base) tag now.
After calling on source activate, I've found following conda activate commands to work: i.e. conda activate env2-name
What didn't work for Git Bash (as a VS Code terminal) for me: activate
env-name and conda activate env-name.

A year later I am still running into this issue. The following is a streamlined and updated approach based on Arafat's answer.
Install Git Bash
Configure Git Bash to be used in VSC (see How do I use Bash on Windows from the Visual Studio Code integrated terminal?)
Open the git bash Terminal from VSC
If conda activate is run successfully, skip the rest
run
conda init bash
Check for the exiting bash dot files:
ls -al ~/.bash*
Likely only one of '.bashrc' and '.bash_profile' exist
Check the existing dot file for conda initialization code
e.g.
cat ~/.bash_profile
This included in my case '>>> conda initialize >>> ...' code
(But, and this is the source of the problem, it is not executed when the terminal is opened. To check which of the files is executed simple add 'echo hello-X' to each of them.)
To fix the problem, we must create the missing dot file and make it execute the OTHER previously existing one:
tee -a ~/.bashrc << END
if [ -f ~/.bash_profile ]; then
source ~/.bash_profile
fi
END
Reopen the Terminal in VSC

python27 and python3 are not not recognized as an internal or external command, operable program or batch file [duplicate]

I am using Python 3.5.2 version on Windows 7 and tried using python3 app.py. I am getting this error message:
'python3' is not recognized as an internal or external command,
operable program or batch file.
Is there any specific cause about why the python3 command is not working?
I also verified that the PATH is added to environment variables.

There is no python3.exe file, that is why it fails.
Try:
py
instead.
py is just a launcher for python.exe. If you have more than one python versions installed on your machine (2.x, 3.x) you can specify what version of python to launch by
py -2 or
py -3

You can also try this:
Go to the path where Python is installed in your system. For me it was something like C:\Users\\Local Settings\Application Data\Programs\Python\Python37
In this folder, you'll find a python executable. Just create a duplicate and rename it to python3. Works every time.

Python3.exe is not defined in windows
Specify the path for required version of python when you need to used it by creating virtual environment for your project
Python 3
virtualenv --python=C:\PATH_TO_PYTHON\python.exe environment
Python2
virtualenv --python=C:\PATH_TO_PYTHON\python.exe environment
then activate the environment using
.\environment\Scripts\activate.ps1

Yes, I think for Windows users you need to change all the python3 calls to python to solve your original error. This change will run the Python version set in your current environment. If you need to keep this call as it is (aka python3) because you are working in cross-platform or for any other reason, then a work around is to create a soft link. To create it, go to the folder that contains the Python executable and create the link. For example, this worked in my case in Windows 10 using mklink:
cd C:\Python3
mklink python3.exe python.exe
Use a (soft) symbolic link in Linux:
cd /usr/bin/python3
ln -s python.exe python3.exe

In my case I have a git hook on commit, specified by admin. So it was not very convenient for me to change the script (with python3 calls).
And the simplest workaround was just to copy python.exe to python3.exe.
Now I could launch both python and python3.

If python2 is not installed on your computer, you can try with just python instead of python3

For Python 27
virtualenv -p C:\Python27\python.exe django_concurrent_env
For Pyton36
virtualenv -p C:\Python36\python.exe django_concurrent_env

Enter the command to start up the server in that directory:
py -3.7 -m http.server

I had a related issue after installing windows 11, where python3 in cmd would open the windows store. I was able to sort it out between this post and this other one. In short, I reinstalled python and made sure to add it to PATH. Then, in settings, Apps > Apps & Features > App Execution aliases. Here, all I had to do was make sure that every single python .exe (including idle and pip) were turned off EXCEPT FOR the python3.exe alias. Now it works like a charm.
FWIW:
The root of this issue is not with you or with python. Apparently, Microsoft wanted to make installing python easier for young kiddos getting interested in coding, so they automatically add an executable to PATH. For those of us that already have this executable, it can cause these issues.

Found out instead press the play button the top right and it should work in visual studios:
Do not disable according to first answer
Saying python3 in the command will not work by default.
After figuring out the problem with the modules (Solution): https://youtu.be/paRXeLurjE4
Summary:
To import python modules in case of problem to import modules:
Hover over python in search:
Click open in folder
Hover over and right click
click properties
copy everything in path before \python.exe
close those windows
For cmd (administrator):
cd --path that was copied--
then python -m pip install --upgrade pip
cd Scripts
pip install "Name of Package" such as pip install --module (package) --

Im on win10 and have 3.7, 3.8 and 3.10 installed.
For me "python" launches version 3.10 and does not accept commands (like -3.7), "py" launches newest version but does accept commands, and "python3" does nothing.
Uninstalled 3.10 and "python" now does nothing, and "py" launches 3.8.

I am unable to add a comment, but the mlink option presented in this answer above https://stackoverflow.com/a/55229666/8441472 by #Stanislav preserves cross-platform shebangs at the top of scripts (#!/usr/bin/env python3) and launches the right python.
(Even if you install python from python.org, Windows will direct you to the app marketplace nowadays if you type python3 on the command line. If you type python on the same cli it will launch the python.org version repl. It leads to scripts that generate no output, but more likely silently failed completely. I don't know ho common this is but have experienced it on a couple of different devices)
If you have this at the top of your script to ensure you launch python3 and don't feel like editing everything you own, it is not a bad approach at all... lol.