macos – 在Mac上安装和导入Python 2和3的站点包

我安装了brew然后

brew install python
brew install python3

用pip安装烧瓶

pip install flask

尝试

python -c 'import flask'

但我得到了例外

ImportError: No module named flask

设置并导出PYTHONPATH

export PYTHONPATH=$PYTHONPATH:/usr/local/lib/python2.7/site-packages

到现在为止还挺好.但是当我尝试使用pip3为Python 3安装软件包时,我收到了错误消息

Your PYTHONPATH points to a site-packages dir for Python 2.x but you are running Python 3.x!
     PYTHONPATH is currently: ":/usr/local/lib/python2.7/site-packages"
     You should `unset PYTHONPATH` to fix this.

如何在没有PYTHONPATH技巧的情况下使用site-packages来使pip和pip3都可用,并且Python 2和Python 3都可以导入站点包？

解决方法:

您应该考虑为此安装pyenv.

pyenv lets you easily switch between multiple versions of Python. It’s simple, unobtrusive, and follows the UNIX Tradition of single-purpose tools that do one thing well.

要安装,只需输入：

$brew install pyenv

将其添加到.bash_profile：

echo 'export PYENV_ROOT="$HOME/.pyenv"' >> ~/.bash_profile
echo 'export PATH="$PYENV_ROOT/bin:$PATH"' >> ~/.bash_profile
echo 'eval "$(pyenv init -)"' >> ~/.bash_profile

安装后使用pyenv安装你需要的python版本：

$pyenv install -l/--list --> List all available versions
$pyenv install 2.7.6
$pyenv install 3.3.3

安装python版本后运行此命令：

$pyenv rehash

您可以一次通过PYENV_VERSION指定多个版本.假设你有两个版本的2.7.6和3.3.3.如果你喜欢2.7.6而不是3.3.3,

$pyenv shell 2.7.6 3.3.3
$pyenv versions
  system
* 2.7.6 (set by PYENV_VERSION environment variable)
* 3.3.3 (set by PYENV_VERSION environment variable)
$python --version
Python 2.7.6
$python2.7 --version
Python 2.7.6
$python3.3 --version
Python 3.3.3