我所做的就是下载2.7.6和3.3.4。Python 3.3.4提供了在环境变量中添加路径的选项，这样就完成了。所以基本上我只是手动添加了Python 2.7.6。

如何……

Start > in the search type in environment select "Edit environment variables to your account"1 Scroll down to Path, select path, click edit. Add C:\Python27; so you should have paths to both versions of Python there, but if you don't this you can easily edit it so that you do..... C:\Python27;C:\Python33; Navigate to the Python27 folder in C:\ and rename a copy of python.exe to python2.exe Navigate to the Python34 folder in C:\ and rename a copy of python.exe to python3.exe Test: open up commmand prompt and type python2 ....BOOM! Python 2.7.6. exit out. Test: open up commmand prompt and type python3 ....BOOM! Python 3.4.3. exit out.

注意:(为了不破坏步骤4和5中的pip命令，将python.exe的副本保存在与重命名文件相同的目录中)

Windows版本有Python启动器，请参阅3.4节。Windows Python启动器

只有在Python IDE中运行代码才有效

我的windows操作系统上同时安装了Python 2.7和Python 3.3。如果我试图启动一个文件，它通常会在python 2.7 IDE上打开。我如何解决这个问题，是当我选择在python 3.3上运行我的代码时，我打开python 3.3 IDLE(python GUI)，选择文件，用IDLE打开我的文件并保存它。然后，当我运行我的代码时，它运行到我当前打开它的IDLE。反之亦然。

我所做的就是下载2.7.6和3.3.4。Python 3.3.4提供了在环境变量中添加路径的选项，这样就完成了。所以基本上我只是手动添加了Python 2.7.6。

如何……

Start > in the search type in environment select "Edit environment variables to your account"1 Scroll down to Path, select path, click edit. Add C:\Python27; so you should have paths to both versions of Python there, but if you don't this you can easily edit it so that you do..... C:\Python27;C:\Python33; Navigate to the Python27 folder in C:\ and rename a copy of python.exe to python2.exe Navigate to the Python34 folder in C:\ and rename a copy of python.exe to python3.exe Test: open up commmand prompt and type python2 ....BOOM! Python 2.7.6. exit out. Test: open up commmand prompt and type python3 ....BOOM! Python 3.4.3. exit out.

注意:(为了不破坏步骤4和5中的pip命令，将python.exe的副本保存在与重命名文件相同的目录中)

我使用一个简单的解决方案从一个版本切换到另一个版本的python，你可以安装所有你想要的版本。你所要做的就是创造一些可变的环境。 在我的例子中，我已经安装了python 2.7和python 3.8.1，所以我创建了以下环境变量:

PYTHON_HOME_2.7 = < path_python_2.7 > PYTHON_HOME_3.8.1 = < path_python_3.8.1 > PYTHON_HOME = % PYTHON_HOME_2.7%

然后在PATH环境变量中只放入%PYTHON_HOME%和%PYTHON_HOME%\Scripts。在上面的例子中，我使用的是2.7版本，当我想切换到其他版本时，我只需要设置PYTHON_HOME=%PYTHON_HOME_3.8.1%。 我使用这种方法可以快速地从一个版本切换到另一个版本，同样适用于JAVA、MAVEN、GRADLE、ANT等等。

You can install multiple versions of Python one machine, and during setup, you can choose to have one of them associate itself with Python file extensions. If you install modules, there will be different setup packages for different versions, or you can choose which version you want to target. Since they generally install themselves into the site-packages directory of the interpreter version, there shouldn't be any conflicts (but I haven't tested this). To choose which version of python, you would have to manually specify the path to the interpreter if it is not the default one. As far as I know, they would share the same PATH and PYTHONPATH variables, which may be a problem.

注:我使用的是Windows XP。我不知道其他版本是否会有这些变化，但我看不出有任何理由会发生变化。