Python multi-version control software under macOS installation: pyenv, pyenv-virtualenv

Software Description :

pyenv, Is a particularly useful version of Python manager, a programmer can create a different directory, run different versions of Python in different directories separately and independently of each other, the installation package also affect each other. github project Address: https://github.com/yyuu/pyenv

pyenv-virtualenvIs pyenva plugin (plugin), can be used to create a clean virtual environment based on different versions of Python. github project Address: https://github.com/yyuu/pyenv-virtualenv

Installation idea :
to install macOS package manager brew, then brewinstall pyenvandpyenv-virtualenv

1. Install `brew`Package Manager

brew full name Homebrew , is macOS a package manager under (macOS not have its own package manager), similar to CentOS belowyum, Ubuntu underapt-getcommand.

1	/usr/bin/ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)"

2. Use the `brew`command to install `pyenv`,`pyenv-virtualenv`

1 2	brew install pyenv brew install pyenv-virtualenv

Will be installed autoconf, pkg-config, openssl,readline

Installation process, we can see some Caveats (warning), we need to manually handle it.
First link readline to the system lib:

1	brew link readline --force

According Caveats then prompts modify environment variables, vim ~/.bash_profileadd the following content:

      
      
       
       #pyenv settings
      
      
      
      
       
       export PYENV_ROOT=/usr/local/var/pyenv
      
      
      
      
       
       if which pyenv > /dev/null; then eval "$(pyenv init -)"; fi
      
      
      
      
      
      
       
       #pyenv-virtualenv settings
      
      
      
      
       
       if which pyenv-virtualenv-init > /dev/null; then eval "$(pyenv virtualenv-init -)"; fi

The above two settings to make pyenvand pyenv-virtualenveasier to use, can be used when the command completion.

Setting up the terminal closed, and then restart the terminal, it can take effect.

3. pyenv to use

**警告：pyenv安装Python是编译安装的，在使用之前要先安装zlib和SQLite3，要不然安装会报错。

安装zlib和SQLite3并链接：

      
      
       
       brew install zlib
      
      
      
      
       
       brew install sqlite3
      
      
      
      
       
       brew link zlib --force
      
      
      
      
       
       brew link sqlite3 --force

然后根据Caveats的提示修改环境变量，vim ~/.bash_profile添加下面内容：

1 2	export PATH= "/usr/local/opt/sqlite/bin:$PATH"

用pyenv --help可以查看pyenv的使用帮助：

常用的几个pyenv命令：

pyenv install x.y.z：安装大专栏 macOS下Python多版本控制软件的安装：pyenv、pyenv-virtualenvPython，x.y.z是Python的版本，如pyenv install 3.6.2。

pyenv local x.y.z：设置当前目录的Python版本为x.y.z, 如pyenv local 3.6.2。

pyenv versions：查看安装的版本，前面带*号的表示当前目录下正在使用的版本。系统自带的Python是System，后安装的版本的都是版本号。

下面给出使用的例子：
示例：

      
      
      
      
      
      
       
       $ pyenv install 3.6.2   
       
       # 安装3.6.2版本的Python
      
      
      
      
       
       $ pyenv install 2.7.13  
       
       # 安装2.7.13版本的Python
      
      
      
      
       
       $ pyenv versions        
       
       # 可以看到3个版本，system为系统自带的版本
      
      
      
      
       
       * system (
       
       set by /usr/
       
       local/var/pyenv/version)
      
      
      
      
       
         2.7.13
      
      
      
      
       
         3.6.2
      
      
      
      
      
      
       
       $ 
       
       cd                   
       
       # 到家目录
      
      
      
      
       
       $ mkdir Python36       
       
       # 创建Python3.6的工作目录
      
      
      
      
       
       $ 
       
       cd Python36
      
      
      
      
       
       $ pyenv 
       
       local 3.6.2    
       
       # 使当前工作目录使用Python3.6.2版本
      
      
      
      
       
       $ python -V            
       
       # 查看一下当前目录用Python的版本，确实是3.6.2
      
      
      
      
       
       Python3.6.2
      
      
      
      
       
       $ pip -V               
       
       # 查看一下pip版本,是3.6的pip
      
      
      
      
       
       pip 9.0.1 from /usr/
       
       local/var/pyenv/versions/3.6.2/lib/python3.6/site-packages 
      
      
      
      
       
       $ 
       
       cd                   
       
       # 回到家目录
      
      
      
      
       
       $ mkdir Python27       
       
       # 创建python2.7的工作目录
      
      
      
      
       
       $ 
       
       cd Python27
      
      
      
      
       
       $ pyenv 
       
       local 2.7.13   
       
       # 使当前工作目录使用Python2.7.13版本
      
      
      
      
       
       $ python -V            
       
       # 查看一下当前目录用Python的版本，确实是2.7.13
      
      
      
      
       
       Python 2.7.13
      
      
      
      
       
       $ pip -V               
       
       # 查看一下pip版本，是2.7的pip
      
      
      
      
       
       pip 9.0.1 from /usr/
       
       local/var/pyenv/versions/2.7.13/lib/python2.7/site-packages (python 2.7)

4. `pyenv-virtualenv`的使用方法

pyenv-virtualenv是用来创建一个干净的虚拟Python环境的命令，通常在创建干净的新项目时候使用。使用方法如下:

1.创建虚拟环境–pyenv virtualenv 版本号虚拟环境名。

1	$ pyenv virtualenv 3.6.2 venv-3.6.2

创建项目，让项目使用干净的Python3.6.2的虚拟环境：

      
      
       
       [yulongjun@yulongjun ~]$ mkdir Learning-Python3
      
      
      
      
       
       [yulongjun@yulongjun ~]$ 
       
       cd Learning-Python3/
      
      
      
      
       
       [yulongjun@yulongjun Learning-Python3]$ pyenv 
       
       local venv-3.6.2
      
      
      
      
       
       (venv-3.6.2) [yulongjun@yulongjun Learning-Python3]$ 
       
       cd ..
      
      
      
      
       
       [yulongjun@yulongjun ~]$ 
       
       cd Learning-Python3/
      
      
      
      
       
       (venv-3.6.2) [yulongjun@yulongjun Learning-Python3]$

We will find: As long as we enter the Learning-Python3directory, it will automatically activate virtualenv, exit the Learning-Python3directory, it will shut down virtualenv.

If you want to turn off automatic activation, you can run the command pyenv deactivateto re-enable it, run pyenv activate 虚拟环境名.