python venv version code example

Example 1: how to check opencv version using python

$ python # "python3"- if you are using another version of python
>>>import cv2
>>>cv2.__version__

Example 2: create a venv

# Create the virtual environment.
python -m venv venv

# Activate the env.
venv\Scripts\activate.bat

Example 3: python create virtualenv

pip install virtualenv # install first
cd projectfolder # go to project folder
python -m venv ./venv # Create a virtual environment named venv
Activate.ps1 # (powershell) start the file  to start the environment
activate.bat # (cmd) start the file  to start the environment
# if it worked you'll see a (venv) in front of your cursor path

Example 4: how to create a new virtualenv

to make a new virtualenv: 
virtualenv env_name

             to activate this virtual environment:
source env_name/bin/activate (on mac and linux)
source env_name/Scripts/activate (on windows)

Example 5: how to use virtual environment python

source env/bin/activate

Example 6: virtualenv specify python version

virtualenv --python=/usr/bin/python2.6 <path/to/new/virtualenv/>