how to work on virtual environment 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: python virtual environment

python3 -m pip install --user virtualenv

Example 4: how virtual environment in python works

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