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  • 浅谈Python之sys.argv

    (1)sys.argv是什么

    sys模块为进入解释器维护或使用的变量,以及与解释器相关的函数提供了途径。sys.argv在脚本程序中扮演了这样一个角色:将命令行输入的参数作为一个list传入脚本程序,即我们可以在cmd命令形式驱动程序方法下,将设定的参数传入脚本,argv[0]是驱动脚本的名字(由操作系统来决定是否是全路径的名字),如果cmd中,将-c传入,那么argv[0]就是-c,

    分界线中的内容为cmd驱动脚本的详细解释,而关于cmd,-c传入的栗子,本文不再赘述  详见https://jingyan.baidu.com/article/03b2f78c3b38f05ea237ae05.html

    在解释中,我们看到py [launcher-args] [python-args] script [script-args],这里script是脚本名字,而其后的[script-args]正是要传入脚本中sys.argv的列表,从argv[1]开始。下面举个简单的例子:

    import sys
    a=sys.argv[0]
    b=sys.argv[1]
    c=sys.argv[2]
    print('argv0:%s'% a)
    print('argv1:%s'% b)
    print('argv2:%s'%c)

    以上代码命名为sys_argvTest.py

    然后在cmd中运行:

    可以看到在脚本名字 后面的'thisisargv1' 'thisisargv2'分别传入了脚本中的sys.argv[1],sys.argv[2]中

    ---------------------------------------------------------------------------------------这是一道华丽的分界线--------------------------------------------------------------------------------------------------------------------------

    usage:
    py [launcher-args] [python-args] script [script-args]
    Launcher arguments:
    -2     : Launch the latest Python 2.x version
    -3     : Launch the latest Python 3.x version
    -X.Y   : Launch the specified Python version
         The above all default to 64 bit if a matching 64 bit python is present.
    -X.Y-32: Launch the specified 32bit Python version
    -X-32  : Launch the latest 32bit Python X version
    -X.Y-64: Launch the specified 64bit Python version
    -X-64  : Launch the latest 64bit Python X version
    -0  --list       : List the available pythons
    -0p --list-paths : List with paths
    The following help text is from Python:
    usage: C:UsersOptions 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     : 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
    -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
    --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>python{major}{minor}.
    PYTHONCASEOK : ignore case in 'import' statements (Windows).
    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, 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.
    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.
    ---------------------------------------------------------------------------------------这是一道华丽的分界线-------------------------------------------------------------------------------------------------------------------------
    ##### 愿你一寸一寸地攻城略地,一点一点地焕然一新 #####
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  • 原文地址:https://www.cnblogs.com/johnyang/p/10479868.html
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