how to activate virtual env python code example

Example 1: virtual env create python

#------FOR LINUX/MAC---------#
#installing venv 
sudo apt-get install python3.6-venv
#creating virtual env
python3 -m venv env
#activating virtual env
source env/bin/activate


#-------FOR WINDOWS----------#
#installing venv
py -m pip install --user virtualenv
#creating virtual env
py -m venv env
#activating virtual env
.\env\Scripts\activate

Example 2: create environment python windows 10

python3 -m venv venv

Example 3: how to activate venv python

(tutorial-env) $ python -m pip install -r requirements.txt
Collecting novas==3.1.1.3 (from -r requirements.txt (line 1))
  ...
Collecting numpy==1.9.2 (from -r requirements.txt (line 2))
  ...
Collecting requests==2.7.0 (from -r requirements.txt (line 3))
  ...
Installing collected packages: novas, numpy, requests
  Running setup.py install for novas
Successfully installed novas-3.1.1.3 numpy-1.9.2 requests-2.7.0