Python：如何在 pyenv-virtual-environment 中更新 python 版本？

Question

I used pyenv , pyenv-virtualenv for managing python virtual environment.

I have a project working in Python 3.4 virtual environment.

So all installed packages( pandas , numpy etc) are not newest version.

What I want to do is to upgrade Python version from 3.4 to 3.6 as well as upgrade other package version to higher one.

How can I do this easily?

Answer 1

Here is how I switched to 3.9.0 :

$ pip freeze > requirements-lock.txt
$ pyenv virtualenv-delete a-virtualenv-name
$ pyenv virtualenv 3.9.0 a-virtualenv-name
$ pip install -r requirements-lock.txt
$ rm requirements-lock.txt

Using pip freeze > requirements.txt is usually not a good idea as this file is often used to handle your package requirements ( not necessarily pip freeze output). It's better to use a different (temporary) file just to be sure.

Answer 2

Use pip freeze > requirements.txt to save a list of installed packages.

Create a new venv with python 3.6.

Install saved packages with pip install -r requirements.txt . When pip founds an universal wheel in its cache it installs the package from the cache. Other packages will be downloaded, cached, built and installed.

Answer 3

If you use anaconda, just type

conda install python==$pythonversion$