Mac 安装 Python 看这里就够了，Python2Python3 再也不懵了

Posted 2023-04-03 DevOps前进四

Mac 安装 Python2、Python3 。

零、基础准备

• 官网
  • https://www.python.org/
• 下载入口
  • https://www.python.org/downloads/
  • https://www.python.org/downloads/macos/

一、安装包下载及安装

安装包下载的页面路径是：官网>>> Downloads>>> macOS

其他平台根据请自己的实际情况选择

安装包下载的页面路径也可以是：官网>>> Downloads(点击)

进入到版本选择页面

最上面是最新的 Release 版本，分别是2.x的最新版本和3.x的最新版。

可以下载最新的 Release 版本进行安装，也可以通过搜索选择自己想要的版本进行安装。

通过搜索找到「2.7.16」

通过搜索找到「3.9.9」

强烈推荐下载最新的 Release 版进行安装

点击对应的链接分别下载即可(下载的过程中注意操作系统的架构和位数)。

👆下载「2.7.18」

👆下载「3.10.6」

👆下载好的安装包

使用下载好的安装包一直「下一步」即可安装对应版本的 python。

二、安装确认

1、Python2

• 查看版本号

$ python -V
Python 2.7.18

• 帮助命令

$ python -h
usage: /Library/Frameworks/Python.framework/Versions/2.7/Resources/Python.app/Contents/MacOS/Python [option] ... [-c cmd | -m mod | file | -] [arg] ...
Options and arguments (and corresponding environment variables):
-b     : issue warnings about comparing bytearray with unicode
         (-bb: issue errors)
-B     : don't write .py[co] files on import; also PYTHONDONTWRITEBYTECODE=x
-c cmd : program passed in as string (terminates option list)
-d     : debug output from parser; also PYTHONDEBUG=x
-E     : ignore PYTHON* environment variables (such as PYTHONPATH)
-h     : print this help message and exit (also --help)
-i     : inspect interactively after running script; forces a prompt even
         if stdin does not appear to be a terminal; also PYTHONINSPECT=x
-m mod : run library module as a script (terminates option list)
-O     : optimize generated bytecode slightly; also PYTHONOPTIMIZE=x
-OO    : remove doc-strings in addition to the -O optimizations
-R     : use a pseudo-random salt to make hash() values of various types be
         unpredictable between separate invocations of the interpreter, as
         a defense against denial-of-service attacks
-Q arg : division options: -Qold (default), -Qwarn, -Qwarnall, -Qnew
-s     : don't add user site directory to sys.path; also PYTHONNOUSERSITE
-S     : don't imply 'import site' on initialization
-t     : issue warnings about inconsistent tab usage (-tt: issue errors)
-u     : unbuffered binary stdout and stderr; also PYTHONUNBUFFERED=x
         see man page for details on internal buffering relating to '-u'
-v     : verbose (trace import statements); also PYTHONVERBOSE=x
         can be supplied multiple times to increase verbosity
-V     : print the Python version number and exit (also --version)
-W arg : warning control; arg is action:message:category:module:lineno
         also PYTHONWARNINGS=arg
-x     : skip first line of source, allowing use of non-Unix forms of #!cmd
-3     : warn about Python 3.x incompatibilities that 2to3 cannot trivially fix
file   : program read from script file
-      : program read from stdin (default; interactive mode if a tty)
arg ...: arguments passed to program in sys.argv[1:]

Other environment variables:
PYTHONSTARTUP: file executed on interactive startup (no default)
PYTHONPATH   : ':'-separated list of directories prefixed to the
               default module search path.  The result is sys.path.
PYTHONHOME   : alternate <prefix> directory (or <prefix>:<exec_prefix>).
               The default module search path uses <prefix>/pythonX.X.
PYTHONCASEOK : ignore case in 'import' statements (Windows).
PYTHONIOENCODING: Encoding[:errors] used for stdin/stdout/stderr.
PYTHONHASHSEED: if this variable is set to 'random', the effect is the same
   as specifying the -R option: a random value is used to seed the hashes of
   str, bytes and datetime objects.  It can also be set to an integer
   in the range [0,4294967295] to get hash values with a predictable seed.

2、Python3

• 查看版本号

$ python3 -V
Python 3.10.6

• 帮助命令

$ python3 -h
usage: /Library/Frameworks/Python.framework/Versions/3.10/bin/python3 [option] ... [-c cmd | -m mod | file | -] [arg] ...
Options and arguments (and corresponding environment variables):
-b     : issue warnings about str(bytes_instance), str(bytearray_instance)
         and comparing bytes/bytearray with str. (-bb: issue errors)
-B     : don't write .pyc files on import; also PYTHONDONTWRITEBYTECODE=x
-c cmd : program passed in as string (terminates option list)
-d     : turn on parser debugging output (for experts only, only works on
         debug builds); also PYTHONDEBUG=x
-E     : ignore PYTHON* environment variables (such as PYTHONPATH)
-h     : print this help message and exit (also -? or --help)
-i     : inspect interactively after running script; forces a prompt even
         if stdin does not appear to be a terminal; also PYTHONINSPECT=x
-I     : isolate Python from the user's environment (implies -E and -s)
-m mod : run library module as a script (terminates option list)
-O     : remove assert and __debug__-dependent statements; add .opt-1 before
         .pyc extension; also PYTHONOPTIMIZE=x
-OO    : do -O changes and also discard docstrings; add .opt-2 before
         .pyc extension
-q     : don't print version and copyright messages on interactive startup
-s     : don't add user site directory to sys.path; also PYTHONNOUSERSITE
-S     : don't imply 'import site' on initialization
-u     : force the stdout and stderr streams to be unbuffered;
         this option has no effect on stdin; also PYTHONUNBUFFERED=x
-v     : verbose (trace import statements); also PYTHONVERBOSE=x
         can be supplied multiple times to increase verbosity
-V     : print the Python version number and exit (also --version)
         when given twice, print more information about the build
-W arg : warning control; arg is action:message:category:module:lineno
         also PYTHONWARNINGS=arg
-x     : skip first line of source, allowing use of non-Unix forms of #!cmd
-X opt : set implementation-specific option. The following options are available:
         -X faulthandler: enable faulthandler
         -X showrefcount: output the total reference count and number of used
             memory blocks when the program finishes or after each statement in the
             interactive interpreter. This only works on debug builds
         -X tracemalloc: start tracing Python memory allocations using the
             tracemalloc module. By default, only the most recent frame is stored in a
             traceback of a trace. Use -X tracemalloc=NFRAME to start tracing with a
             traceback limit of NFRAME frames
         -X importtime: show how long each import takes. It shows module name,
             cumulative time (including nested imports) and self time (excluding
             nested imports). Note that its output may be broken in multi-threaded
             application. Typical usage is python3 -X importtime -c 'import asyncio'
         -X dev: enable CPython's "development mode", introducing additional runtime
             checks which are too expensive to be enabled by default. Effect of the
             developer mode:
                * Add default warning filter, as -W default
                * Install debug hooks on memory allocators: see the PyMem_SetupDebugHooks()
                  C function
                * Enable the faulthandler module to dump the Python traceback on a crash
                * Enable asyncio debug mode
                * Set the dev_mode attribute of sys.flags to True
                * io.IOBase destructor logs close() exceptions
         -X utf8: enable UTF-8 mode for operating system interfaces, overriding the default
             locale-aware mode. -X utf8=0 explicitly disables UTF-8 mode (even when it would
             otherwise activate automatically)
         -X pycache_prefix=PATH: enable writing .pyc files to a parallel tree rooted at the
             given directory instead of to the code tree
         -X warn_default_encoding: enable opt-in EncodingWarning for 'encoding=None'
--check-hash-based-pycs always|default|never:
    control how Python invalidates hash-based .pyc files
file   : program read from script file
-      : program read from stdin (default; interactive mode if a tty)
arg ...: arguments passed to program in sys.argv[1:]

Other environment variables:
PYTHONSTARTUP: file executed on interactive startup (no default)
PYTHONPATH   : ':'-separated list of directories prefixed to the
               default module search path.  The result is sys.path.
PYTHONHOME   : alternate <prefix> directory (or <prefix>:<exec_prefix>).
               The default module search path uses <prefix>/lib/pythonX.X.
PYTHONPLATLIBDIR : override sys.platlibdir.
PYTHONCASEOK : ignore case in 'import' statements (Windows).
PYTHONUTF8: if set to 1, enable the UTF-8 mode.
PYTHONIOENCODING: Encoding[:errors] used for stdin/stdout/stderr.
PYTHONFAULTHANDLER: dump the Python traceback on fatal errors.
PYTHONHASHSEED: if this variable is set to 'random', a random value is used
   to seed the hashes of str and bytes objects.  It can also be set to an
   integer in the range [0,4294967295] to get hash values with a
   predictable seed.
PYTHONMALLOC: set the Python memory allocators and/or install debug hooks
   on Python memory allocators. Use PYTHONMALLOC=debug to install debug
   hooks.
PYTHONCOERCECLOCALE: if this variable is set to 0, it disables the locale
   coercion behavior. Use PYTHONCOERCECLOCALE=warn to request display of
   locale coercion and locale compatibility warnings on stderr.
PYTHONBREAKPOINT: if this variable is set to 0, it disables the default
   debugger. It can be set to the callable of your debugger of choice.
PYTHONDEVMODE: enable the development mode.
PYTHONPYCACHEPREFIX: root directory for bytecode cache (pyc) files.
PYTHONWARNDEFAULTENCODING: enable opt-in EncodingWarning for 'encoding=None'.

三、其他

除了使用python、python3命令来调用对应版本的 python 外，还可以使用如下的命令来调用对应版本的 python。

$ python2 -V
Python 2.7.18
$ python2.7 -V
Python 2.7.18
$ python3.10 -V
Python 3.10.6

这些都可以可以在 /usr/local/bin 这个目录下看到相关命令对应的「软连接」。

$ pwd
/usr/local/bin
$ ls -l | grep python
python -> ../../../Library/Frameworks/Python.framework/Versions/2.7/bin/python
python-config -> ../../../Library/Frameworks/Python.framework/Versions/2.7/bin/python-config
python2 -> ../../../Library/Frameworks/Python.framework/Versions/2.7/bin/python2
python2-config -> ../../../Library/Frameworks/Python.framework/Versions/2.7/bin/python2-config
python2.7 -> ../../../Library/Frameworks/Python.framework/Versions/2.7/bin/python2.7
python2.7-config -> ../../../Library/Frameworks/Python.framework/Versions/2.7/bin/python2.7-config
python3 -> ../../../Library/Frameworks/Python.framework/Versions/3.10/bin/python3
python3-config -> ../../../Library/Frameworks/Python.framework/Versions/3.10/bin/python3-config
python3-intel64 -> ../../../Library/Frameworks/Python.framework/Versions/3.10/bin/python3-intel64
python3.10 -> ../../../Library/Frameworks/Python.framework/Versions/3.10/bin/python3.10
python3.10-config -> ../../../Library/Frameworks/Python.framework/Versions/3.10/bin/python3.10-config
python3.10-intel64 -> ../../../Library/Frameworks/Python.framework/Versions/3.10/bin/python3.10-intel64
pythonw -> ../../../Library/Frameworks/Python.framework/Versions/2.7/bin/pythonw
pythonw2 -> ../../../Library/Frameworks/Python.framework/Versions/2.7/bin/pythonw2
pythonw2.7 -> ../../../Library/Frameworks/Python.framework/Versions/2.7/bin/pythonw2.7

PS：python2和python3的兼容性一直被广大开发者诟病。

Python 安装环境搭建看这一篇就够了（Windows+Mac+Linux）

Windows

1. 下载Python安装包

访问Python官网（www.python.org），点击页面上的“Downloads”，选择你的操作系统：

笔者的电脑是Windows 10系统，所以进入了Windows的下载页面，我们要下载Python的最新版，因此点击下载区域的“Latest Python 3 Release - Python 3.9.5“，如图：

当然，如果要下载指定版本，你也可以在“Stable Releases”中找到需求版本。
进入了Python3.9.5的安装包下载页面，翻滚到最底部，找到下载表格：

根据系统位数选择安装包并下载。

2. 运行Python安装包

打开下载的安装包exe，如图：

等待进度条，安装完毕后，退出页面：

3. IDLE编辑器使用

IDLE是Python自带的集成开发环境，首先在开始菜单中搜索“IDLE”，打开搜索到的程序：

键入指令：

>>> print("Hello, world !")

接下来学习如何新建，保存和运行一个Python程序。

点击菜单栏中的“File” --> “New File”，新建文件并写入代码：

再次点击“FIie” --> “Save”，保存Python文件。

然后，点击“Run” --> “Run Module”， 运行程序：

作者：wangzirui32 原文链接：https://blog.csdn.net/wangzirui32/article/details/117156716

Mac

1. 下载安装文件

访问Python官网（www.python.org），选取稳定版本，如：macOS 64-bit installer点击下载。

2. 安装文件

打开下载的安装文件，按照提示信息点击“继续”安装，直至安装完成。

3. 配置mac默认版本是python3

打开终端，输入命令which python3，查看python3的安装目录

将路径配入环境变量。

在文件最后加上alias python="/Library/Frameworks/Python.framework/Versions/3.8/bin/python3"，保存并退出

在终端输入source ~/.bash_profile使其生效，查看当前python版本：

作者：lemon柚子 原文链接：https://blog.csdn.net/lemontree_cxs/article/details/107431120

Linux

Linux，centos系统本身默认安装有python2.x，版本x根据不同版本系统有所不同，可通过 python --V 或 python --version 查看系统自带的python版本

有一些系统命令时需要用到python2，不能卸载

1. 安装依赖包

1）首先安装gcc编译器，gcc有些系统版本已经默认安装，通过  gcc --version  查看，没安装的先安装gcc，yum -y install gcc

2）安装其它依赖包，（注：不要缺少，否则有可能安装python出错，python3.7.0以下的版本可不装 libffi-devel ）

yum-yinstallzlib-develbzip2-devel openssl-devel ncurses-devel sqlite-devel readline-devel tk-devel gdbm-devel db4-devel libpcap-devel xz-devel libffi-devel

2. 下载python3.7.3源码，根据需求下载

1）去python官网下载源码包

https://www.python.org/ftp/python/3.7.2/Python-3.7.2.tgz

2）下载

3）解压Python-3.7.2.tgz

tar -zvxf Python-3.7.2.tgz

3. 建立一个空文件夹，用于存放python3程序

mkdir/usr/local/python3  //做完了需要每次新建单个文件夹 mkdir usr 建完之后 cd usr 到usr文件夹继续建剩下，步骤一致

4. 执行配置文件，编译，编译安装

cd Python-3.7.2 先进去桌面已经解压文件
在执行下面这段 ./configure --prefix=/usr/local/python3 &&make &&make install
安装完成没有提示错误便安装成功了

5. 建立软连接

ln -s /usr/local/python3/bin/python3.7/usr/bin/python3
ln -s /usr/local/python3/bin/pip3.7/usr/bin/pip3

6. 测试一下python3是否可以用

如果Python3 查看不到Python3.7.2版本，需要添加系统变量
export PATH=$PATH:$HOME/bin:/usr/local/python3/bin  这个只是当前窗口临时查看
复制代码

7. 添加永久系统变量

通过修改profile文件:

执行 vim /etc/profile
/export PATH //找到设置PATH的行，添加
export PATH=/usr/local/python37/bin:$PATH
:wq  //保存文件并退出vi

生效方法：

• 系统重启

• 要想马上生效还要运行

# source /etc/profile

不然只能在下次重进此用户时生效。

有效期限：永久有效 用户局限：对所有用户

到这里，就可以执行查看到Python 3.7.2版本！

作者：灰太狼的精神 原文链接：https://juejin.cn/post/6844903987146145800

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