create virtual env using python code example

Example 1: virtual environment python

### VIRTUAL ENVIRONMENT 

pip install virtualenv

virtualenv pas # write the folder name 

.\foldername\Scripts\activate # to activate the virtual environment 

pip freeze # to get all the modules in the base interpretor / virtual env

pip freeze > requirements.txt # to set the modules and their versions in the requirement file 

pip install -r requirements.txt # to install all the modules with their respected versions in the virtual env

virtualenv --system-site-packages-foldername # this creates virtual env with all the modules and versions that are preinstalled on base python interpretor 

deactivate # to come out of the virtual env

Example 2: create a virtualenv python3

py -m venv env