Mac python多版本環境

Mac下python多版本

1. 須要安裝pyenv以支持多pytohn版本環境
2. 須要安裝virtualenv以支持python包環境隔離
3. 但pyenv提供了virtualenv的插件，因此咱們直接安裝插件便可
4. 通常安裝了virtualenv後會安裝virtualenvwrapper簡化virtualenv的操做，可是pyenv的virtualenv的插件已經作了這個工做，再也不建議安裝pyenv-virtualenvwrapper（具體見這裏）
5. 因此咱們安裝pyenv以及virtualenv的插件便可

 

安裝步驟：

如下安裝採用brew

1. 查找是否有pyenv包

# Teron @ TeronsMac in ~ [22:26:16]
$ brew search pyenv
==> Searching local taps...
pyenv                      pyenv-pip-migrate          pyenv-virtualenvwrapper
pyenv-ccache               pyenv-virtualenv           pyenv-which-ext
==> Searching taps on GitHub...
==> Searching blacklisted, migrated and deleted formulae...

2. 安裝pyenv

# Teron @ TeronsMac in ~ [22:26:36]
$ brew install pyenv
Updating Homebrew...
==> Auto-updated Homebrew!
Updated 1 tap (homebrew/core).
==> Updated Formulae
angular-cli                mongoose                   shairport-sync
convox                     paket                      vim
docker-machine-parallels   povray                     xorriso
mongo-c-driver             pygobject3                 xtensor

==> Downloading https://homebrew.bintray.com/bottles/pyenv-1.1.3.sierra.bottle.t
Already downloaded: /Users/Teron/Library/Caches/Homebrew/pyenv-1.1.3.sierra.bottle.tar.gz
==> Pouring pyenv-1.1.3.sierra.bottle.tar.gz
🍺  /usr/local/Cellar/pyenv/1.1.3: 581 files, 2.2MB

3. brew list查看pyenv是否安裝

# Teron @ TeronsMac in ~ [22:29:43]
$ brew list
autoconf		openssl			readline
brew-cask-completion	pkg-config		sqlite
gdbm			pyenv			xz
makedepend		python3

4. pyenv -v 查看已安裝

# Teron @ TeronsMac in ~ [22:32:00]
$ pyenv -v
pyenv 1.1.3

# Teron @ TeronsMac in ~ [22:32:08]
$ pyenv versions
* system (set by /Users/Teron/.python-version)

5. pyenv基本命令

$ pyenv version        # 查看當前系統使用的python版本
$ pyenv versions        # 查看當前系統擁有的python版本
$ pyenv install --list： # 列出全部能夠下載的python版本.
$ pyenv install 3.4.1          # 安裝3.4.1，可以使用-v參數查看詳細輸出
$ pyenv uninstall 3.4.1         # 卸載
$ pyenv local 3.4.1     # local僅對當前目錄及子目錄生效，告訴當前目錄使用版本2.7.5，
$ pyenv global          # 告訴全局環境使用某個版本，爲了避免破壞系統環境，不建議使用global設置全局版本
$ pyenv rehash          # 重建環境變量，每當你增刪 Python 版本或帶有可執行文件的包（如 pip）之後，都應該執行一次本命令

6. 安裝python2.7.13，3.6.2版本

# Teron @ TeronsMac in ~ [22:36:26] C:2
$ pyenv install 2.7.13
Downloading Python-2.7.13.tar.xz...
-> https://www.python.org/ftp/python/2.7.13/Python-2.7.13.tar.xz
Installing Python-2.7.13...
Installed Python-2.7.13 to /Users/Teron/.pyenv/versions/2.7.13


# Teron @ TeronsMac in ~ [22:38:33]
$ pyenv install 3.6.2
Installing Python-3.6.2...
Installed Python-3.6.2 to /Users/Teron/.pyenv/versions/3.6.2

# Teron @ TeronsMac in ~ [22:42:55]
$ pyenv versions
* system (set by /Users/Teron/.python-version)
  2.7.13
  3.6.2

# Teron @ TeronsMac in ~ [22:43:55]
$ pyenv rehash //Run this command after you install a new version of Python, or install a package that provides binaries.

7. 切換版本，發現沒切過去，須要執行if which pyenv > /dev/null; then eval "$(pyenv init -)"; fi

# Teron @ TeronsMac in ~ [22:43:32]
$ pyenv local 2.7.13

# Teron @ TeronsMac in ~ [23:17:58]
$ python -V
Python 2.7.10

# Teron @ TeronsMac in ~ [23:20:15]
$ if which pyenv > /dev/null; then eval "$(pyenv init -)"; fi

# Teron @ TeronsMac in ~ [23:20:29]
$ python -V
Python 2.7.13

8. 須要往當前用戶shell配置文件中寫入以上配置，個人是zsh環境，則在.zshrc文件最後寫入

if which pyenv > /dev/null; then eval "$(pyenv init -)"; fi

pyenv的魔法可以實現是由於它實際上重定義了你的Python命令：

$ which python
/Users/Teron/.pyenv/shims/python

當你嘗試運行Python的時候，它首先查看當前目錄下的.python-version目錄來決定到底哪一個版本的Python該運行。若是它沒有發現這個文件，那麼它以後回繼續查找用戶級別的文件~/.pyenv/version。

 

9. 安裝pyenv-virtualenv

# Teron @ TeronsMac in ~ [23:23:49]
$ brew install pyenv-virtualenv
Updating Homebrew...
==> Auto-updated Homebrew!
Updated 1 tap (homebrew/core).
==> Updated Formulae
ruby-build                               streamlink

==> Downloading https://github.com/yyuu/pyenv-virtualenv/archive/v1.1.0.tar.gz
Already downloaded: /Users/Teron/Library/Caches/Homebrew/pyenv-virtualenv-1.1.0.tar.gz
==> ./install.sh
==> Caveats
To enable auto-activation add to your profile:
  if which pyenv-virtualenv-init > /dev/null; then eval "$(pyenv virtualenv-init -)"; fi
==> Summary
🍺  /usr/local/Cellar/pyenv-virtualenv/1.1.0: 20 files, 60.2KB, built in 1 second

# Teron @ TeronsMac in ~ [23:24:31]
$ brew list
autoconf		openssl			python3
brew-cask-completion	pkg-config		readline
gdbm			pyenv			sqlite
makedepend		pyenv-virtualenv	xz

10. 安裝完同時也要在.zshrc中加入以下內容

if which pyenv-virtualenv-init > /dev/null; then eval "$(pyenv virtualenv-init -)"; fi

11. pyenv-virtualenv usage

pyenv virtualenv 2.7.13 env-test：建立名爲env-test的虛擬環境，對應的版本爲2.7.13
pyenv activate env-test：切換到env-test虛擬環境
pyenv deactivate：退回系統環境

# Teron @ TeronsMac in ~ [23:28:10]
$ pyenv virtualenv 2.7.13 env-test
Collecting virtualenv
  Using cached virtualenv-15.1.0-py2.py3-none-any.whl
Installing collected packages: virtualenv
Successfully installed virtualenv-15.1.0
New python executable in /Users/Teron/.pyenv/versions/2.7.13/envs/env-test/bin/python2.7
Also creating executable in /Users/Teron/.pyenv/versions/2.7.13/envs/env-test/bin/python
Installing setuptools, pip, wheel...done.
Requirement already satisfied: setuptools in /Users/Teron/.pyenv/versions/2.7.13/envs/env-test/lib/python2.7/site-packages
Requirement already satisfied: pip in /Users/Teron/.pyenv/versions/2.7.13/envs/env-test/lib/python2.7/site-packages

# Teron @ TeronsMac in ~ [23:31:23]
$ pyenv versions
  system
  2.7.13
  2.7.13/envs/env-test
* 3.6.2 (set by /Users/Teron/.python-version)
  env-test

#### 後面的 set by /Users/Teron/.python-version意思指：
#### 我當前目錄是/Users/Teron/，pyenv設置版本時，其實是在當前目錄建立.python-version文件記錄版本; 

$ cat .python-version
3.6.2


# Teron @ TeronsMac in ~ [23:31:34]
$ pyenv activate env-test

Failed to activate virtualenv.

Perhaps pyenv-virtualenv has not been loaded into your shell properly.
Please restart current shell and try again.

# 按要求重啓終端窗口ok了

# Teron @ TeronsMac in ~ [23:32:47]
$ pyenv activate env-test
pyenv-virtualenv: prompt changing will be removed from future release. configure `export PYENV_VIRTUALENV_DISABLE_PROMPT=1' to simulate the behavior.
(env-test)

# Teron @ TeronsMac in ~ [23:32:50]
$ pip list
DEPRECATION: The default format will switch to columns in the future. You can use --format=(legacy|columns) (or define a format=(legacy|columns) in your pip.conf under the [list] section) to disable this warning.
pip (9.0.1)
setuptools (36.4.0)
wheel (0.30.0)
(env-test)
# Teron @ TeronsMac in ~ [23:33:53]
$ pip install requests
Collecting requests
  Retrying (Retry(total=4, connect=None, read=None, redirect=None)) after connection broken by 'NewConnectionError('<pip._vendor.requests.packages.urllib3.connection.VerifiedHTTPSConnection object at 0x10bffbb90>: Failed to establish a new connection: [Errno 65] No route to host',)': /simple/requests/
  Downloading requests-2.18.4-py2.py3-none-any.whl (88kB)
    100% |████████████████████████████████| 92kB 104kB/s
Collecting certifi>=2017.4.17 (from requests)
  Downloading certifi-2017.7.27.1-py2.py3-none-any.whl (349kB)
    100% |████████████████████████████████| 358kB 54kB/s
Collecting chardet<3.1.0,>=3.0.2 (from requests)
  Downloading chardet-3.0.4-py2.py3-none-any.whl (133kB)
    100% |████████████████████████████████| 143kB 48kB/s
Collecting idna<2.7,>=2.5 (from requests)
  Downloading idna-2.6-py2.py3-none-any.whl (56kB)
    100% |████████████████████████████████| 61kB 30kB/s
Collecting urllib3<1.23,>=1.21.1 (from requests)
  Downloading urllib3-1.22-py2.py3-none-any.whl (132kB)
    100% |████████████████████████████████| 133kB 18kB/s
Installing collected packages: certifi, chardet, idna, urllib3, requests
Successfully installed certifi-2017.7.27.1 chardet-3.0.4 idna-2.6 requests-2.18.4 urllib3-1.22
(env-test)
# Teron @ TeronsMac in ~ [23:34:44]
$ pip list
DEPRECATION: The default format will switch to columns in the future. You can use --format=(legacy|columns) (or define a format=(legacy|columns) in your pip.conf under the [list] section) to disable this warning.
certifi (2017.7.27.1)
chardet (3.0.4)
idna (2.6)
pip (9.0.1)
requests (2.18.4)
setuptools (36.4.0)
urllib3 (1.22)
wheel (0.30.0)
(env-test)

# Teron @ TeronsMac in ~ [23:35:04]
$ pyenv deactivate

# Teron @ TeronsMac in ~ [23:35:35]
$ pip list
DEPRECATION: The default format will switch to columns in the future. You can use --format=(legacy|columns) (or define a format=(legacy|columns) in your pip.conf under the [list] section) to disable this warning.
pip (9.0.1)
setuptools (28.8.0)

# deactivate 後，pip list看不到env-test裏安裝的requests，環境隔離了

12. 列出全部的virtual環境，以及刪除某個環境

# Teron @ TeronsMac in ~ [23:35:39]
$ pyenv virtualenvs
  2.7.13/envs/env-test (created from /Users/Teron/.pyenv/versions/2.7.13)
  env-test (created from /Users/Teron/.pyenv/versions/2.7.13)

# Teron @ TeronsMac in ~ [23:37:59]
$ pyenv uninstall env-test
pyenv-virtualenv: remove /Users/Teron/.pyenv/versions/2.7.13/envs/env-test? y

# Teron @ TeronsMac in ~ [23:39:01]
$ pyenv virtualenvs

# 可見剛纔的env-test環境已經沒了

# Teron @ TeronsMac in ~ [23:39:18]
$ pyenv versions
  system
  2.7.13
* 3.6.2 (set by /Users/Teron/.python-version)

 

如下是針對各個易混淆的概念作的說明

PyPI packages not in the standard library:

• virtualenv is a very popular tool that creates isolated Python environments for Python libraries. If you're not familiar with this tool, I highly recommend learning it, as it is a very useful tool, and I'll be making comparisons to it for the rest of this answer.

  It works by installing a bunch of files in a directory (eg: env/), and then modifying the PATHenvironment variable to prefix it with a custom bin directory (eg: env/bin/). An exact copy of the python or python3 binary is placed in this directory, but Python is programmed to look for libraries relative to its path first, in the environment directory. It's not part of Python's standard library, but is officially blessed by the PyPA (Python Packaging Authority). Once activated, you can install packages in the virtual environment using pip.

• pyenv is used to isolate Python versions. For example, you may want to test your code against Python 2.6, 2.7, 3.3, 3.4 and 3.5, so you'll need a way to switch between them. Once activated, it prefixes the PATH environment variable with ~/.pyenv/shims, where there are special files matching the Python commands (python, pip). These are not copies of the Python-shipped commands; they are special scripts that decide on the fly which version of Python to run based on the PYENV_VERSION environment variable, or the .python-versionfile, or the ~/.pyenv/version file. pyenv also makes the process of downloading and installing multiple Python versions easier, using the command pyenv install.

• pyenv-virtualenv is a plugin for pyenv by the same author as pyenv, to allow you to use pyenv and virtualenv at the same time conveniently. However, if you're using Python 3.3 or later, pyenv-virtualenv will try to run python -m venv if it is available, instead of virtualenv. You can use virtualenv and pyenv together without pyenv-virtualenv, if you don't want the convenience features.

• virtualenvwrapper is a set of extensions to virtualenv (see docs). It gives you commands like mkvirtualenv, lssitepackages, and especially workon for switching between different virtualenv directories. This tool is especially useful if you want multiple virtualenv directories.

• pyenv-virtualenvwrapper is a plugin for pyenv by the same author as pyenv, to conveniently integrate virtualenvwrapper into pyenv.

• pipenv, by Kenneth Reitz (the author of requests), is a brand new (possibly experimental) project that aims to combine Pipfile, pip and virtualenv into one command on the command-line.

Standard library:

• pyvenv is a script shipped with Python 3 but deprecated in Python 3.6 as it had problems (not to mention the confusing name). In Python 3.6+, the exact equivalent is python3 -m venv.

• venv is a package shipped with Python 3, which you can run using python3 -m venv(although for some reason some distros separate it out into a separate distro package, such as python3-venv on Ubuntu/Debian). It serves a similar purpose to virtualenv, and works in a very similar way, but it doesn't need to copy Python binaries around (except on Windows). Use this if you don't need to support Python 2. At the time of writing, the Python community seems to be happy with virtualenv and I haven't heard much talk of venv.