A quick look up for python virtual environment table

Heads Up: virtual environments are meant to be environments for you dependencies and your packages and things like that for your project. But they are not actually for your project files. Your project should not be inside your virtual env folder. Your project should be in another folder.

Install virtualenv:

$pip install virtualenv

List all the packages in the current env:

$pip list

Make a directory:

$mkdir Environments

Make the virtual environment:

$virtualenv project1_env

Activate the new python environment:

$source project1_env/bin/activate

Now we are inside our new virtual environment, we could check that by the prompt of the terminal. We can also check it by

$which python, or $which python3, or $which pip

Now $pip list will only show the packages installed in this virtual env, and $pip install numpy would only install the numpy package in the current environment.

Export all the packages in the current virtual env so I might want to use the same set up for another virtual env:

$pip freeze --local > requiremets.txt

Notice: you could also use your global side packages within a virtual python env. The command would only take the local (virtual env) dependencies that you had in your virtual python env and put them into requirements.txt

Get out of the python virtual environment: $deactivate

Delete the virtual env: $rm -rf project1_env

Make a virtual python env with a specific python version(e.g.3 ): $virtualenv -p /usr/bin/python3 py3_env the Path after the -p flag may vary

Activate the env: $source py3_env/bin/activate

Install all the dependencies from requirement.txt: $pip install -r requirements.txt

Thanks to https://www.youtube.com/watch?v=N5vscPTWKOk