Build a venv virtual environment in Python

 

Python3.3 and above versions natively support virtual environments through the venv module, which can replace the virtualenv before Python.

The venv module provides the creation of a lightweight "virtual environment" and provides isolation support from the system Python. Each virtual environment has its own Python binary (different Python version creation environments are allowed), and can have its own independent set of Python packages. His biggest advantage is that each python project can use a separate environment without affecting the python system environment or the environment of other projects.

advantage

1. Make different application development environments independent
2. Environment upgrade does not affect other applications, nor does it affect the global python environment
3. Prevent package management confusion and version conflicts in the system

windows create virtual environment

Installed python3 environment, my python version is python3.5

My example here is to create a py3 directory in the root directory of the c drive and
enter the py3 directory

Create a virtual environment
python -m evnv c:\py3\

After the command is executed, you will see the following files in the py3 directory

Activate the virtual environment
or operate under windows cmd:
enter Scripts, execute activate.bat, the following figure shows that the activation is successful

At this time, you can enter python3 in the virtual environment and install the packages we need without affecting the python3 package environment installed by our system. Here I installed the pymysql package in the virtual environment, and then pip in the virtual environment and the outside environment. list lists the packages, you can see that there is no pymysql package in our external package

We have configured such a virtual environment

Mac or linux to create a virtual environment

In fact, there is not much difference between the methods of the three platforms, here is demonstrated through the Mac system, the python environment is still python3.5

Still create a py3 directory, and then enter the py3 directory

localhost:py3 zhaofan$ pwd
/Users/zhaofan/py3

Create a virtual environment

python3 -m venv .

Activate the virtual environment

source bin/activate

As shown below:

Then the virtual environment is created

 

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