How to install and use virualenv in python virtual environment

Preface after installing python, pip, setuptools, and other tools, you can create a virualenv virtual environment, which is similar to a virtual machine tool, it is a good development tool that allows the same brain to run multiple python programs of different versions without affecting each other. you can exit or delete them when you don't need them. 1. install virtualenv # installpiponmacbrewinstallpythoncurlhttps Preface
After installing python, pip, setuptools, and other tools, you can create a virualenv virtual environment. This tool is similar to a virtual machine and allows the same brain to run multiple python programs of different versions, don't affect each other. you can exit or delete it when you don't need it. it's a good development tool.
1. install virtualenv

#install pip on macbrew install pythoncurl https://bootstrap.pypa.io/ez_setup.py -o - | sudo pythonsudo easy_install pip#install virtualenv by pippip install virtualenv

II. Use of virtualenv

# Create a new environment called pythonEnv virtualenv pythonEnv # activate and then use cd pythonEnvsource bin/activate # exit the environment deactivate

III. use virtualenvwrapper to manage virtual environments
Install virtualenvwrapper

pip install virtualenvwrapper

Configure environment variables:

vim ~/.bash_profile# Virtualenv/VirtualenvWrappersource /usr/local/bin/virtualenvwrapper.sh# exit vimsource ~/.bash_profile

Create environment

Mkvirtualenv pythonEnv # In ~ /Envs create the pythonEnv folder mkvirtualenv python3Env-p python3.5 # create the python3.5 environment

Switch environment:

workon pythonEnv

Exit environment:

deactivate

Delete environment:

rmvirtualenv pythonEnv

Others
1. other commands

Lsvirtualenv # List all environments. Cdvirtualenv # navigate to the Directory of the activated virtual environment. for example, you can browse its site-packages. Cdsitepackages # is similar to the above, but directly enters the site-packages directory. Lssitepackages # displays the content in the site-packages directory.

2. the ImportError: No module named extern error occurs when pip is installed using the easy_install command.
Cause: The extern module of python2.7.12 in mac is not installed.
Solution:

#download from https://pypi.python.org/pypi/extern/0.1.0 tar zxf extern-0.1.0.tar.gz && python setup.py install

The above describes how to install and use virualenv in the python virtual environment. For more information, see other related articles in the first PHP community!