求助：如何在virtual env wrapper中升级Python至>=3.7？pip安装失败

Ah, I get it—moving from Anaconda to virtualenvwrapper can feel a bit jarring at first, since their approach to environment and Python version management is totally different. Let's break down why your pip commands aren't working, and how to fix this properly.

First, why your pip attempts failed #

Unlike Anaconda (which manages its own Python distributions and can "upgrade" Python within an environment), pip is designed to manage Python packages, not the Python interpreter itself. Running commands like pip install -U python or pip install python>=3.7 will never work because there's no official "python" package on PyPI that replaces your system/interpreter version.

The correct approach for virtualenvwrapper #

Virtualenvwrapper creates environments that are tied to a specific Python interpreter version at creation time. You can't upgrade the Python version inside an existing environment—instead, you need to create a new environment using your target Python version. Here's how:

1. Verify you have Python >=3.7 installed on your system
   First, check if the desired Python version exists on your machine. Run this in your terminal:

   python3.7 --version
   

   If this returns a version number (e.g., Python 3.7.16), you're good to go. If not, you'll need to install Python 3.7+ via your system's package manager (like apt on Ubuntu, brew on macOS, or download it from the official Python website).

2. Find the path to your target Python interpreter
   Use the which command to get the full path to the Python 3.7+ executable:

   which python3.7
   

   This will output something like /usr/bin/python3.7 or /usr/local/bin/python3.8—keep this path handy.

3. Create a new virtual environment with the target Python version
   Use mkvirtualenv with the --python flag to specify the interpreter path:

   mkvirtualenv --python=/path/to/your/python3.7 my_new_env
   

   Replace /path/to/your/python3.7 with the path you got from step 2, and my_new_env with whatever name you want for your environment.

4. Migrate packages from your old environment (optional)
   If you want to carry over the packages from your existing environment:

   • Activate your old environment first:

     workon your_old_env
     

   • Export the list of installed packages:

     pip freeze > requirements.txt
     

   • Activate your new environment:

     workon my_new_env
     

   • Install the packages from the requirements file:

     pip install -r requirements.txt
     

Key Notes #

• Never try to upgrade the Python interpreter inside an existing virtualenvwrapper environment—it's not supported, and will likely break your environment.
• Virtualenvwrapper relies on system-installed Python versions, so you need to have the target version installed on your machine first (unlike Anaconda, which can install Python versions for you within its ecosystem).

内容的提问来源于stack exchange，提问作者thanatoz