why virtual environmentto have a space where we can install packages specific to a certain project
example for updating from Django 1 to Django 2
each project should have its own packages separate from each other
demo: need *Python 3.3 or higher*
pip3 list
create a new virtual environment - 2:57 *python3 -m venv project_env* (project_env is the name of the project to be initialized)
activate the created virtual environment - 3:45 *source* project_env/bin/activate
For those folks (like me) using the fish shell, at around the mark you'll need to enter *source py3env/bin/**activate.fish* in the terminal otherwise you'll most likely get an error like this:
If you need to use a different version of python
if other wants to export the packages that are used 5:39 *requirement.txt*
Exporting packages from your environment with requirements.txt file
*pip freeze*
in Linux: *pip freeze > requirements.txt*
deactivate the project
Creating a new virtual environment (Best practice)
*** normal practice of using venv*
use of the created requirements.txt
Creating a virtual environment from a requirements.txt file
*pip install -r requirements.txt*
one thing to mention: *it is common to put virtual environment inside your project folder, but you don't want to put project files into your virtual environment*
you shouldn't commit your virtual environment to your source control
what should be committed in version control: your requirements.txt
Deactivating environment
how to create an environment with access to system-packages
Creating a virtual environment containing all system packages
--system-site-packages
the additional packages installed in this environment won't affect the system packages
Listing packages you've installed within the environment (not system packages)
