### 导航 - [索引](../genindex.xhtml "总目录") - [模块](../py-modindex.xhtml "Python 模块索引") | - [下一页](logging.xhtml "模块 logging --- Python 的日志记录工具") | - [上一页](argparse.xhtml "argparse --- 命令行选项、参数和子命令解析器") | -  - [Python](https://www.python.org/) » - zh\_CN 3.7.3 [文档](../index.xhtml) » - [Python 标准库](index.xhtml) » - [通用操作系统服务](allos.xhtml) » - $('.inline-search').show(0); | # [`getopt`](#module-getopt "getopt: Portable parser for command line options; support both short and long option names.") --- C-style parser for command line options **Source code:** [Lib/getopt.py](https://github.com/python/cpython/tree/3.7/Lib/getopt.py) \[https://github.com/python/cpython/tree/3.7/Lib/getopt.py\] 注解 The [`getopt`](#module-getopt "getopt: Portable parser for command line options; support both short and long option names.") module is a parser for command line options whose API is designed to be familiar to users of the C `getopt()` function. Users who are unfamiliar with the C `getopt()` function or who would like to write less code and get better help and error messages should consider using the [`argparse`](argparse.xhtml#module-argparse "argparse: Command-line option and argument parsing library.") module instead. - - - - - - This module helps scripts to parse the command line arguments in `sys.argv`. It supports the same conventions as the Unix `getopt()` function (including the special meanings of arguments of the form '`-`' and '`--`'). Long options similar to those supported by GNU software may be used as well via an optional third argument. This module provides two functions and an exception: `getopt.``getopt`(*args*, *shortopts*, *longopts=\[\]*)Parses command line options and parameter list. *args* is the argument list to be parsed, without the leading reference to the running program. Typically, this means `sys.argv[1:]`. *shortopts* is the string of option letters that the script wants to recognize, with options that require an argument followed by a colon (`':'`; i.e., the same format that Unix `getopt()` uses). 注解 Unlike GNU `getopt()`, after a non-option argument, all further arguments are considered also non-options. This is similar to the way non-GNU Unix systems work. *longopts*, if specified, must be a list of strings with the names of the long options which should be supported. The leading `'--'` characters should not be included in the option name. Long options which require an argument should be followed by an equal sign (`'='`). Optional arguments are not supported. To accept only long options, *shortopts* should be an empty string. Long options on the command line can be recognized so long as they provide a prefix of the option name that matches exactly one of the accepted options. For example, if *longopts* is `['foo', 'frob']`, the option `--fo` will match as `--foo`, but `--f` will not match uniquely, so [`GetoptError`](#getopt.GetoptError "getopt.GetoptError") will be raised. The return value consists of two elements: the first is a list of ``` (option, value) ``` pairs; the second is the list of program arguments left after the option list was stripped (this is a trailing slice of *args*). Each option-and-value pair returned has the option as its first element, prefixed with a hyphen for short options (e.g., `'-x'`) or two hyphens for long options (e.g., `'--long-option'`), and the option argument as its second element, or an empty string if the option has no argument. The options occur in the list in the same order in which they were found, thus allowing multiple occurrences. Long and short options may be mixed. `getopt.``gnu_getopt`(*args*, *shortopts*, *longopts=\[\]*)This function works like [`getopt()`](#module-getopt "getopt: Portable parser for command line options; support both short and long option names."), except that GNU style scanning mode is used by default. This means that option and non-option arguments may be intermixed. The [`getopt()`](#module-getopt "getopt: Portable parser for command line options; support both short and long option names.") function stops processing options as soon as a non-option argument is encountered. If the first character of the option string is `'+'`, or if the environment variable `POSIXLY_CORRECT` is set, then option processing stops as soon as a non-option argument is encountered. *exception* `getopt.``GetoptError`This is raised when an unrecognized option is found in the argument list or when an option requiring an argument is given none. The argument to the exception is a string indicating the cause of the error. For long options, an argument given to an option which does not require one will also cause this exception to be raised. The attributes `msg` and `opt` give the error message and related option; if there is no specific option to which the exception relates, `opt` is an empty string. *exception* `getopt.``error`Alias for [`GetoptError`](#getopt.GetoptError "getopt.GetoptError"); for backward compatibility. An example using only Unix style options: ``` >>> import getopt >>> args = '-a -b -cfoo -d bar a1 a2'.split() >>> args ['-a', '-b', '-cfoo', '-d', 'bar', 'a1', 'a2'] >>> optlist, args = getopt.getopt(args, 'abc:d:') >>> optlist [('-a', ''), ('-b', ''), ('-c', 'foo'), ('-d', 'bar')] >>> args ['a1', 'a2'] ``` Using long option names is equally easy: ``` >>> s = '--condition=foo --testing --output-file abc.def -x a1 a2' >>> args = s.split() >>> args ['--condition=foo', '--testing', '--output-file', 'abc.def', '-x', 'a1', 'a2'] >>> optlist, args = getopt.getopt(args, 'x', [ ... 'condition=', 'output-file=', 'testing']) >>> optlist [('--condition', 'foo'), ('--testing', ''), ('--output-file', 'abc.def'), ('-x', '')] >>> args ['a1', 'a2'] ``` In a script, typical usage is something like this: ``` import getopt, sys def main(): try: opts, args = getopt.getopt(sys.argv[1:], "ho:v", ["help", "output="]) except getopt.GetoptError as err: # print help information and exit: print(err) # will print something like "option -a not recognized" usage() sys.exit(2) output = None verbose = False for o, a in opts: if o == "-v": verbose = True elif o in ("-h", "--help"): usage() sys.exit() elif o in ("-o", "--output"): output = a else: assert False, "unhandled option" # ... if __name__ == "__main__": main() ``` Note that an equivalent command line interface could be produced with less code and more informative help and error messages by using the [`argparse`](argparse.xhtml#module-argparse "argparse: Command-line option and argument parsing library.") module: ``` import argparse if __name__ == '__main__': parser = argparse.ArgumentParser() parser.add_argument('-o', '--output') parser.add_argument('-v', dest='verbose', action='store_true') args = parser.parse_args() # ... do something with args.output ... # ... do something with args.verbose .. ``` 参见 Module [`argparse`](argparse.xhtml#module-argparse "argparse: Command-line option and argument parsing library.")Alternative command line option and argument parsing library. ### 导航 - [索引](../genindex.xhtml "总目录") - [模块](../py-modindex.xhtml "Python 模块索引") | - [下一页](logging.xhtml "模块 logging --- Python 的日志记录工具") | - [上一页](argparse.xhtml "argparse --- 命令行选项、参数和子命令解析器") | -  - [Python](https://www.python.org/) » - zh\_CN 3.7.3 [文档](../index.xhtml) » - [Python 标准库](index.xhtml) » - [通用操作系统服务](allos.xhtml) » - $('.inline-search').show(0); | © [版权所有](../copyright.xhtml) 2001-2019, Python Software Foundation. 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