python_argparse

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argparse由来

​ 原文：

The argparse module is a command line parsing library which provides more functionality than the existing command line parsing modules in the standard library, getopt [2] and optparse [3]. It includes support for positional arguments (not just options), subcommands, required options, options syntaxes like “/f” and “+rgb”, zero-or-more and one-or-more style arguments, and many other features the other two lack.

The argparse module is also already a popular third-party replacement for these modules. It is used in projects like IPython (the Scipy Python shell) [4], is included in Debian testing and unstable [5], and since 2007 has had various requests for its inclusion in the standard library [6] [7] [8]. This popularity suggests it may be a valuable addition to the Python libraries.

个人理解：

argparse 是一个命令行分析库，它比标准库中的getopt optparse要强大。argparse属于目前流行的第三方命令分析库。

命令解析模块必知的一些基础概念

位置参数

如 ls /home/XXX  其中的 ‘/home/XXX’就称之为位置参数

可选参数

如 ls -l 其中的 ‘-l’ 就称之为可选参数

帮助文档

如 ls --help

入门dome1

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import argparse

parse = argparse.ArgumentParser()
parse.parse_args()

用来创建一个基础的命令程序

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import argparse

parse = argparse.ArgumentParser()
parse.add_argument('echo',help='回显你输入的字符串')
args = parse.parse_args()
print(args.echo)

当用户使用命令行python 文件名 –help 会查看到
positional arguments:
echo 回显你输入的字符串

positional arguments:

what is positional arguments?

通常它代表命令中的坐标信息，并且它一个必选项参数。

下面的dome演示如何构建及其调用

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import argparse

parse = argparse.ArgumentParser()
parse.add_argument('echo',help='回显你输入的字符串')
parse.add_argument('square',help='计算输入数的平方',type=int)

args = parse.parse_args()
print(args.echo)
print(args.square**2)

当用户使用命令行python 文件名 –help 会查看到
positional arguments:
echo 回显你输入的字符串
square 计算输入数的平方

optional arguments:
-h, –help show this help message and exit

optional arguments

what is optional arguments?

它可以代表命令中的一些附件信息，如下面的2个dome一个是表示选择只有一个参数，一个表示选项可以有多个参数

多参数

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import argparse

parse = argparse.ArgumentParser()

parse.add_argument('--verbosity',help="increase output verbosity")
args = parse.parse_args()

if args.verbosity:
    print('verbosity turned on')
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spiderbao@spiderbao-CW65S:~/python/study/code$ python3 argparse_study.py 
spiderbao@spiderbao-CW65S:~/python/study/code$ python3 argparse_study.py --version
usage: argparse_study.py [-h] [--verbosity VERBOSITY]
spiderbao@spiderbao-CW65S:~/python/study/code$ python3 argparse_study.py 
spiderbao@spiderbao-CW65S:~/python/study/code$ python3 argparse_study.py -h
usage: argparse_study.py [-h] [--verbosity VERBOSITY]

optional arguments:
  -h, --help            show this help message and exit
  --verbosity VERBOSITY
                        increase output verbosity
spiderbao@spiderbao-CW65S:~/python/study/code$ python3 argparse_study.py -verbosity 1
usage: argparse_study.py [-h] [--verbosity VERBOSITY]
argparse_study.py: error: unrecognized arguments: -verbosity 1
spiderbao@spiderbao-CW65S:~/python/study/code$ python3 argparse_study.py --verbosity 1
verbosity turned on
spiderbao@spiderbao-CW65S:~/python/study/code$

单参数

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import argparse

parse = argparse.ArgumentParser()

parse.add_argument('--verbosity',help="increase output verbosity",action='store_true')
args = parse.parse_args()

if args.verbosity:
    print('verbosity turned on')
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spiderbao@spiderbao-CW65S:~/python/study/code$ python3 argparse_study.py --verbosity
verbosity turned on
spiderbao@spiderbao-CW65S:~/python/study/code$ python3 argparse_study.py --verbosity 1
usage: argparse_study.py [-h] [--verbosity]
argparse_study.py: error: unrecognized arguments: 1
spiderbao@spiderbao-CW65S:~/python/study/code$ python3 argparse_study.py -h
usage: argparse_study.py [-h] [--verbosity]

optional arguments:
  -h, --help   show this help message and exit
  --verbosity  increase output verbosity
spiderbao@spiderbao-CW65S:~/python/study/code$

短选项

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import argparse
parse = argparse.ArgumentParser()
parse.add_argument('-v','--verbosity',help='increase output verbosity',action='store_true')
args = parse.parse_args()

if args.verbosity:
  print('verbosity turned on')

命令行输入

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spiderbao@spiderbao-CW65S:~/python/study/code$ python3 argparse_study.py -v 1
verbosity turned on
spiderbao@spiderbao-CW65S:~/python/study/code$ python3 argparse_study.py -v 
verbosity turned on
spiderbao@spiderbao-CW65S:~/python/study/code$ python3 argparse_study.py --verbosity
verbosity turned on

组合Positional和Optional参数

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parse = argparse.ArgumentParser()
parse.add_argument('-v','--verbosity',help='显示输出详情',action='count',default=1)
parse.add_argument('square',help='计算输入数的平方',type=int)
args = parse.parse_args()
answer = args.square**2
if args.verbosity>=1:
  print('%s^2=%s' %(args.square,answer))
if args.verbosity>=2:
  print('runing %s'%__file__)
if args.verbosity<1:
  print(answer)

命令行输入显示

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spiderbao@spiderbao-CW65S:~/python/study/code$ python3 argparse_study.py -h 
usage: argparse_study.py [-h] [-v] square

positional arguments:
  square           计算输入数的平方

optional arguments:
  -h, --help       show this help message and exit
  -v, --verbosity  显示输出详情
spiderbao@spiderbao-CW65S:~/python/study/code$ python3 argparse_study.py -h
usage: argparse_study.py [-h] [-v] square

positional arguments:
  square           计算输入数的平方

optional arguments:
  -h, --help       show this help message and exit
  -v, --verbosity  显示输出详情
spiderbao@spiderbao-CW65S:~/python/study/code$ python3 argparse_study.py 4
4^2=16
spiderbao@spiderbao-CW65S:~/python/study/code$ python3 argparse_study.py 4 -v
4^2=16
runing argparse_study.py
spiderbao@spiderbao-CW65S:~/python/study/code$ python3 argparse_study.py 4 -vv
4^2=16
runing argparse_study.py

选参互斥异常

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parse = argparse.ArgumentParser(description='calculate X to the power of Y')
group = parse.add_mutually_exclusive_group();
group.add_argument("-v", "--verbose", action="store_true")
group.add_argument("-q", "--quiet", action="store_true")
#group 添加互斥项，相当于usage: argparse_study.py [-h] [-v | -q] x y 中的[-v | -q] 只能选取一个
parse.add_argument("x", type=int, help="the base")
parse.add_argument("y", type=int, help="the exponent")
args = parse.parse_args()
answer = args.x**args.y

if args.quiet:
    print(answer)
elif args.verbose:
    print("{} to the power {} equals {}".format(args.x, args.y, answer))
else:
    print("{}^{} == {}".format(args.x, args.y, answer))

命令行输入显示

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spiderbao@spiderbao-CW65S:~/python/study/code$ python3 argparse_study.py -h
usage: argparse_study.py [-h] [-v | -q] x y

calculate X to the power of Y

positional arguments:
  x              the base
  y              the exponent

optional arguments:
  -h, --help     show this help message and exit
  -v, --verbose
  -q, --quiet
spiderbao@spiderbao-CW65S:~/python/study/code$ python3 argparse_study.py 4 2
4^2 == 16
spiderbao@spiderbao-CW65S:~/python/study/code$ python3 argparse_study.py 4 2 -v
4 to the power 2 equals 16
spiderbao@spiderbao-CW65S:~/python/study/code$ python3 argparse_study.py 4 2 -q
16
spiderbao@spiderbao-CW65S:~/python/study/code$ python3 argparse_study.py 4 2 -vq
usage: argparse_study.py [-h] [-v | -q] x y
argparse_study.py: error: argument -q/--quiet: not allowed with argument -v/--verbose

以上内容参考https://docs.python.org/3/howto/argparse.html?highlight=argparse