how to activate a virtual environment in python code example

Example 1: python virtual environment

python3 -m venv env
python -m virtualenv env #py2

source env/bin/activate

#all this is on same directory

Example 2: how to use virtual environment python

python3 -m venv env

Example 3: create virtual environment python 3

python3 -m venv /path/to/new/virtual/environment

Example 4: how to create a virtual environment in python

source env/bin/activate

Example 5: how virtual environment in python works

>>> import sys
>>> sys.prefix
'/System/Library/Frameworks/Python.framework/Versions/3.5'