如何在 ubuntu 上将我的 python 版本从 3.7.5 降级到 3.6.5

Question

所以目前，我有 ubuntu 19。它默认带有 python 3.7.5。我需要降级到 3.6.5。

编辑：

我正在使用 virtualenv

Answer 1

您还可以使用 virtualenv 来使用不同的 Python 环境。

如果您键入 python 并按 Tab 键两次左右，您可能会看到许多 Python 版本可用。我这样说是因为当我输入

python3.6 -V

我有

Python 3.6.9

可用。 python 的别名是 3.7.5

当您键入 python 时，您可能指的是 .bashrc

中定义的别名

Answer 2

下面讨论从 3.6.7 升级到 3.7.0，但您可以使用相同的过程进行降级。你不应该改变系统 python 除非你真的知道你在做什么

首先安装Pyenv

Installlation Instructions are here

查看 Pyenv 选项

$ pyenv 
pyenv 1.2.14
Usage: pyenv <command> [<args>]

Some useful pyenv commands are:
   commands    List all available pyenv commands
   activate    Activate virtual environment
   commands    List all available pyenv commands
   deactivate   Deactivate virtual environment
   doctor      Verify pyenv installation and deevlopment tools to build pythons.
   exec        Run an executable with the selected Python version
   global      Set or show the global Python version
   help        Display help for a command
   hooks       List hook scripts for a given pyenv command
   init        Configure the shell environment for pyenv
   install     Install a Python version using python-build
   local       Set or show the local application-specific Python version
   prefix      Display prefix for a Python version
   rehash      Rehash pyenv shims (run this after installing executables)
   root        Display the root directory where versions and shims are kept
   shell       Set or show the shell-specific Python version
   shims       List existing pyenv shims
   uninstall   Uninstall a specific Python version
   --version   Display the version of pyenv
   version     Show the current Python version and its origin
   version-file   Detect the file that sets the current pyenv version
   version-name   Show the current Python version
   version-origin   Explain how the current Python version is set
   versions    List all Python versions available to pyenv
   virtualenv   Create a Python virtualenv using the pyenv-virtualenv plugin
   virtualenv-delete   Uninstall a specific Python virtualenv
   virtualenv-init   Configure the shell environment for pyenv-virtualenv
   virtualenv-prefix   Display real_prefix for a Python virtualenv version
   virtualenvs   List all Python virtualenvs found in `$PYENV_ROOT/versions/*'.
   whence      List all Python versions that contain the given executable
   which       Display the full path to an executable

See `pyenv help <command>' for information on a specific command.
For full documentation, see: https://github.com/pyenv/pyenv#readme

查看 Python 版本

$ pyenv versions
  system
 * 3.6.7 (set by /home/taarimalta/.pyenv/version)

安装新的 Python

$ pyenv install 3.7.0
Installing Python-3.7.0...
WARNING: The Python bz2 extension was not compiled. Missing the bzip2 lib?
WARNING: The Python readline extension was not compiled. Missing the GNU readline lib?
WARNING: The Python sqlite3 extension was not compiled. Missing the SQLite3 lib?
Installed Python-3.7.0 to /home/taarimalta/.pyenv/versions/3.7.0

如果您运行遇到 _ctypes 安装 libffi-dev 库的问题

现在看看版本


$ pyenv versions
  system
* 3.6.7 (set by /home/taarimalta/.pyenv/version)
  3.7.0

Select 本地环境 3.7.0

$ pyenv local 3.7.0

看到版本变了

$ pyenv versions
  system
  3.6.7
 * 3.7.0 (set by /home/taarimalta/.python-version)

$ python
Python 3.7.0 (default, Jan  1 2020, 10:52:57) 
[GCC 9.2.1 20191008] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>>

切换到不同的文件夹

cd ../project2
pyenv versions
  system
* 3.6.7 (set by /home/taarimalta/.pyenv/version)
  3.7.0

此处的python版本可能会有所不同，具体取决于您在本地设置的python版本

全局设置pyenv版本

这会为用户全局设置 python 版本

pyenv global 3.7.0

请注意，pyenv 通过添加 .python-version 文件来设置本地版本

$ pyenv local 3.7.0
$ cat .python-version
3.7.0

注意pyenv通过查看~/.pyenv/version文件知道全球版本

cat ~/.pyenv/version
3.8.2

Answer 3

从预编译的 Ubuntu deb 包 repos 安装它。

$ sudo apt update
$ sudo apt install software-properties-common

$ sudo add-apt-repository ppa:deadsnakes/ppa

出现提示时，按 ENTER 键继续。

sudo apt install python3.6

如何在 ubuntu 上将我的 python 版本从 3.7.5 降级到 3.6.5

How do I downgrade my version of python from 3.7.5 to 3.6.5 on ubuntu

python

linux

ubuntu

virtualenv