What is a Virtual Environment and How Does it Help Python Developers?

What is a Virtual Environment (Virtualenv)?

When working with Python, you may encounter installation issues and permission errors. To address this, you can utilize virtual environments (virtualenvs), which serve as isolated Python installations.

Virtualenvs offer several benefits:

• Isolation: They keep Python installations separate from the system Python and other environments, preventing package conflicts and system dependency issues.
• Isolation: They allow you to specify the exact Python version and packages used for your projects.
• Control: You can prevent unwanted changes to packages installed within the virtualenv.
• Multiple Environments: You can create multiple virtualenvs for different projects or versions of Python, ensuring that each project has a consistent and isolated environment.

How to Create and Activate a Virtualenv

Python 3.3 :

python3 -m venv ENV_DIR

Windows:

C:\Python34\python.exe -m venv ENV_DIR

Older Python Versions:

virtualenv ENV_DIR
venv ENV_DIR
pyvenv ENV_DIR
pyvenv3 ENV_DIR

To activate the virtualenv:

Unix:

. ./venv/bin/activate

Windows:

venv\Scripts\activate

The shell prompt will now display the virtualenv name to indicate which environment is active.

Using Virtualenv

Once the virtualenv is activated, you can install packages locally using pip:

(venv)$ pip install requests numpy

You can run Python commands within the virtualenv:

(venv)$ python
[...]
>>> import requests
>>> import numpy as np

Deactivating Virtualenv

To exit the virtualenv:

(venv)$ deactivate

Managing Virtualenvs

You can create and remove virtualenvs as needed. To remove a virtualenv, simply delete the directory where it is located.

The above is the detailed content of What is a Virtual Environment and How Does it Help Python Developers?. For more information, please follow other related articles on the PHP Chinese website!