How to install virtualenv:

Install pip first

sudo apt-get install python3-pip

Then install virtualenv using pip3

sudo pip3 install virtualenv 

Now create a virtual environment

virtualenv venv 

you can use any name insted of venv

You can also use a Python interpreter of your choice

virtualenv -p /usr/bin/python2.7 venv

Active your virtual environment:

source venv/bin/activate

Using fish shell:

source venv/bin/activate.fish

To deactivate:

deactivate

Create virtualenv using Python3

virtualenv -p python3 myenv

Instead of using virtualenv you can use this command in Python3

python3 -m venv myenv

原文链接：Creating an virtual environment in python