Mac下python多版本的灵活切换pyenv

python的版本多是一个另初学者很头疼的问题. 可能有些代码是 在python2.*的版本下开发的, 一些安装包也都是在 2.*的环境下使用的. 各类版本混乱的问题随之产生.那要怎么解决这个版本混乱的问题呢?

pyenv

pyenv的介绍

简单的说, pyenv就是管理python版本的工具, 各个版本之间相互独立, 互不干扰.

pyenv的安装

咱们使用brew来安装pyenv, 能够在brew中查看介绍和安装步骤

brew命令相似于RHEL的yum和ubuntu的apt-get命令

安装好brew以后, 咱们使用brew安装pyenv

xxzxdeMacBook-Pro:~ xxzx$ brew install pyenv
xxzxdeMacBook-Pro:~ xxzx$ pyenv -v
pyenv 1.2.8
xxzxdeMacBook-Pro:~ xxzx$ pyenv versions
* system (set by /usr/local/var/pyenv/version)
  3.6.5
xxzxdeMacBook-Pro:~ xxzx$ pyenv install --list
Available versions:
  2.1.3
  2.2.3
  2.3.7
  ...

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• * 表示当前正在使用的版本，system表示用的是系统python版本
• pyenv -v: 查看版本
• pyenv versions: 查看pyenv管理的全部版本
• pyenv install --list: 查看可安装的版本

使用pyenv安装python版本

pyenv安装好以后, 咱们就能够使用了, 但我在使用pyenv install 3.6.5这个命令进行安装的时候出现以下报错

xxzxdeMacBook-Pro:~$ pyenv install 3.6.5
python-build: use openssl from homebrew
python-build: use readline from homebrew
Downloading Python-3.6.5.tar.xz...
-> https://www.python.org/ftp/python/3.6.5/Python-3.6.5.tar.xz
Installing Python-3.6.5...
python-build: use readline from homebrew

BUILD FAILED (OS X 10.14 using python-build 20180424)

Inspect or clean up the working tree at /var/folders/b_/4ggdxx_539g8cqp2wr2m5sph0000gn/T/python-build.20181012094932.14705
Results logged to /var/folders/b_/4ggdxx_539g8cqp2wr2m5sph0000gn/T/python-build.20181012094932.14705.log

Last 10 log lines:
  File "/private/var/folders/b_/4ggdxx_539g8cqp2wr2m5sph0000gn/T/python-build.20181012094932.14705/Python-3.6.5/Lib/ensurepip/__main__.py", line 5, in <module>
    sys.exit(ensurepip._main())
  File "/private/var/folders/b_/4ggdxx_539g8cqp2wr2m5sph0000gn/T/python-build.20181012094932.14705/Python-3.6.5/Lib/ensurepip/__init__.py", line 204, in _main
    default_pip=args.default_pip,
  File "/private/var/folders/b_/4ggdxx_539g8cqp2wr2m5sph0000gn/T/python-build.20181012094932.14705/Python-3.6.5/Lib/ensurepip/__init__.py", line 117, in _bootstrap
    return _run_pip(args + [p[0] for p in _PROJECTS], additional_paths)
  File "/private/var/folders/b_/4ggdxx_539g8cqp2wr2m5sph0000gn/T/python-build.20181012094932.14705/Python-3.6.5/Lib/ensurepip/__init__.py", line 27, in _run_pip
    import pip._internal
zipimport.ZipImportError: can't decompress data; zlib not available make: *** [install] Error 1 复制代码

上面的倒数第二行的zlib not available说zlib不可用, 百度有说使用xcode-select --install便可解决, 我试了无效.

使用brew install zlib 安装zlib

$ brew install zlib
==> Downloading https://homebrew.bintray.com/bottles/zlib-1.2.11.mojave.bottle.t
######################################################################## 100.0%
==> Pouring zlib-1.2.11.mojave.bottle.tar.gz
==> Caveats
zlib is keg-only, which means it was not symlinked into /usr/local,
because macOS already provides this software and installing another version in
parallel can cause all kinds of trouble.

For compilers to find zlib you may need to set:
  export LDFLAGS="-L/usr/local/opt/zlib/lib"
  export CPPFLAGS="-I/usr/local/opt/zlib/include"

For pkg-config to find zlib you may need to set:
  export PKG_CONFIG_PATH="/usr/local/opt/zlib/lib/pkgconfig"

==> Summary
  /usr/local/Cellar/zlib/1.2.11: 12 files, 373KB
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这里要注意的是要配置环境变量

使用vi ~/.bash_profile, 按键盘i插入内容, 以后保存退出便可

export LDFLAGS="-L/usr/local/opt/zlib/lib"
export CPPFLAGS="-I/usr/local/opt/zlib/include"
export PKG_CONFIG_PATH="/usr/local/opt/zlib/lib/pkgconfig"
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使用 source ~/.bash_profile执行一下

xxzxdeMacBook-Pro:~ xxzx$ vi ~/.bash_profile
xxzxdeMacBook-Pro:~ xxzx$ source ~/.bash_profile
xxzxdeMacBook-Pro:~ xxzx$ pyenv install 3.6.5
python-build: use openssl from homebrew
python-build: use readline from homebrew
Downloading Python-3.6.5.tar.xz...
-> https://www.python.org/ftp/python/3.6.5/Python-3.6.5.tar.xz
Installing Python-3.6.5...
python-build: use readline from homebrew
WARNING: The Python sqlite3 extension was not compiled. Missing the SQLite3 lib?
Installed Python-3.6.5 to /usr/local/var/pyenv/versions/3.6.5
xxzxdeMacBook-Pro:~ xxzx$ brew install sqlite
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而后经过brew安装sqlite以后便可成功了. 这个时候咱们再去查看当前的版本

xxzxdeMacBook-Pro:~ xxzx$ pyenv versions
* system (set by /usr/local/var/pyenv/version)
  3.6.5
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切换版本

xxzxdeMacBook-Pro:~ xxzx$ pyenv global 3.6.5  # 全局切换
xxzxdeMacBook-Pro:~ xxzx$ python -V  # 验证一下是否切换成功
xxzxdeMacBook-Pro:~ xxzx$ pyenv local 3.6.5  # 当前目录及其目录切换
xxzxdeMacBook-Pro:~ xxzx$ python -V  # 验证一下是否切换成功
xxzxdeMacBook-Pro:~ xxzx$ pyenv uninstall 3.6.5  # 卸载pyenv管理的python版本
xxzxdeMacBook-Pro:~ xxzx$ pyenv local --unset  # 解除local设置
xxzxdeMacBook-Pro:~ xxzx$ pyevn global system  # 切换回系统版本
xxzxdeMacBook-Pro:~ xxzx$ pyenv commands  # 查看命令
--version
commands
completions
exec
global
help
hooks
init
install
local
prefix
realpath.dylib
rehash
root
shell
shims
uninstall
version
version-file
version-file-read
version-file-write
version-name
version-origin
versions
whence
which
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在这里咱们查看版本的时候可能仍是系统的默认版本, 能够尝试使用python3 -V查看, 若是依然有问题, 咱们须要配置环境变量, 和上面的步骤同样

export PYENV_ROOT=~/.pyenv
export PATH=$PYENV_ROOT/shims:$PATH
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使用pyenv结合虚拟环境则会很是的好用