python3.x命令行解析

使用最基本的方法：

import sys
for arg in sys.argv[0:]:
	print(arg);

测试：

C:\Python33>python test.py
test.py

C:\Python33>python test.py -1 2 --a
test.py
-1
2
--a

使用【 getopt 】库：

import sys
import getopt
agrv = sys.argv[1:];
optlist, args = getopt.getopt(agrv, "ab:c:");
print(optlist);
print(args);

测试：

C:\Python33>python test.py
[]
[]

C:\Python33>python test.py -a -b2
[('-a', ''), ('-b', '2')]
[]

C:\Python33>python test.py -a -b2 -c3
[('-a', ''), ('-b', '2'), ('-c', '3')]
[]

C:\Python33>python test.py -a -b 2 -c 3
[('-a', ''), ('-b', '2'), ('-c', '3')]
[]

C:\Python33>python test.py -a -b2 -c3 4 5
[('-a', ''), ('-b', '2'), ('-c', '3')]
['4', '5']

C:\Python33>python test.py -a -b2 -c3 -d
Traceback (most recent call last):
  File "test.py", line 4, in <module>
    optlist, args = getopt.getopt(agrv, "ab:c:");
  File "C:\Python33\lib\getopt.py", line 95, in getopt
    opts, args = do_shorts(opts, args[0][1:], shortopts, args[1:])
  File "C:\Python33\lib\getopt.py", line 195, in do_shorts
    if short_has_arg(opt, shortopts):
  File "C:\Python33\lib\getopt.py", line 211, in short_has_arg
    raise GetoptError(_('option -%s not recognized') % opt, opt)
getopt.GetoptError: option -d not recognized

可以看到，其扩展性不太好，如果输入错了，就容易出现exception，代码处理起来比较麻烦。官方在文档的最后也推荐了另一个库【 argparse 】。

argparse：

Argparse Tutorial: https://docs.python.org/3/howto/argparse.html#id1
argparse:https://docs.python.org/3/library/argparse.html#module-argparse
【 argparse 】库功能很强大，根据官方的例子，可以直接对输入参数进行加减乘除。。这里作者根据官方的Tutorial，只学习最基本的功能。

空壳：

import argparse
parser = argparse.ArgumentParser();
args = parser.parse_args();

测试：

C:\Python33>python test.py

C:\Python33>python test.py -h
usage: test.py [-h]

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

可以看到，-h选项已经自动生成了。

必选参数：

import argparse
parser = argparse.ArgumentParser();
parser.add_argument("yourname",help="input your name");
args = parser.parse_args();
print("Hello " + args.yourname);

测试：

无参数，报错并提示。
C:\Python33>python test.py
usage: test.py [-h] yourname
test.py: error: the following arguments are required: yourname
无效参数，报错并提示。
C:\Python33>python test.py -x
usage: test.py [-h] yourname
test.py: error: the following arguments are required: yourname
自动生成了提示信息。
C:\Python33>python test.py -h
usage: test.py [-h] yourname

positional arguments:
  yourname    input your name

optional arguments:
  -h, --help  show this help message and exit
正确参数。
C:\Python33>python test.py cstriker1407
Hello cstriker1407

必选int参数：

import argparse
parser = argparse.ArgumentParser();
parser.add_argument("yourname",help="input your name");
parser.add_argument("age",help="input your age",type=int);#有了type
args = parser.parse_args();
print("Hello " + args.yourname + ".Double of your age is " + str(2 * args.age));

测试：

C:\Python33>python test.py cstriker1407 100
Hello cstriker1407.Double of your age is 200

可选输入参数：

import argparse
parser = argparse.ArgumentParser();
parser.add_argument("yourname",help="input your name");
parser.add_argument("--home",help="input your home");
args = parser.parse_args();
print("Hello " + args.yourname);
if args.home:#如果设置了可选参数，这里的home就不是空
	print("Your Home:" + args.home);

测试：

自动生成了帮助文档
C:\Python33>python test.py -h
usage: test.py [-h] [--home HOME] yourname

positional arguments:
  yourname     input your name

optional arguments:
  -h, --help   show this help message and exit
  --home HOME  input your home
输入顺序是没有关系的
C:\Python33>python test.py --home China cstriker1407
Hello cstriker1407
Your Home:China
输入顺序是没有关系的
C:\Python33>python test.py cstriker1407 --home China
Hello cstriker1407
Your Home:China
可选参数，不输入是没有关系的
C:\Python33>python test.py cstriker1407
Hello cstriker1407

可选标志参数：

import argparse
parser = argparse.ArgumentParser();
parser.add_argument("yourname",help="input your name");
parser.add_argument("--verbose",help="print all Info",action="store_true");#注意action
args = parser.parse_args();
print("Hello " + args.yourname);
if args.verbose:
	print("HI, THIS IS A VERBOSE INFO");

测试： 

帮助信息已经改变了
C:\Python33>python test.py -h
usage: test.py [-h] [--verbose] yourname

positional arguments:
  yourname    input your name

optional arguments:
  -h, --help  show this help message and exit
  --verbose   print all Info

C:\Python33>python test.py  cstriker1407
Hello cstriker1407

C:\Python33>python test.py  cstriker1407 --verbose
Hello cstriker1407
HI, THIS IS A VERBOSE INFO

短字符串：

import argparse
parser = argparse.ArgumentParser();
parser.add_argument("yourname",help="input your name");
parser.add_argument("-v","--verbose",help="print all Info",action="store_true");
args = parser.parse_args();
print("Hello " + args.yourname);
if args.verbose:
	print("HI, THIS IS A VERBOSE INFO");

测试：

C:\Python33>python test.py -h
usage: test.py [-h] [-v] yourname

positional arguments:
  yourname       input your name

optional arguments:
  -h, --help     show this help message and exit
  -v, --verbose  print all Info

C:\Python33>python test.py  cstriker1407 -v
Hello cstriker1407
HI, THIS IS A VERBOSE INFO

限制可选输入参数：

import argparse
parser = argparse.ArgumentParser();
parser.add_argument("yourname",help="input your name");
parser.add_argument("--gender",help="input your gender",choices=["male", "female"]);#choice选项
args = parser.parse_args();
print("Hello " + args.yourname + " , your gender is:" + args.gender);

测试：

C:\Python33>python test.py  -h
usage: test.py [-h] [--gender {male,female}] yourname

positional arguments:
  yourname              input your name

optional arguments:
  -h, --help            show this help message and exit
  --gender {male,female}
                        input your gender

C:\Python33>python test.py  cstriker1407 --gender male
Hello cstriker1407 , your gender is:male

C:\Python33>python test.py  cstriker1407 --gender xxx
usage: test.py [-h] [--gender {male,female}] yourname
test.py: error: argument --gender: invalid choice: 'xxx' (choose from 'male', 'female')

这里只是简单的笔记下argparse最简单的使用方法，复杂的以后用到了再笔记吧。

【 optionparser 】库

该库已经deprecated了，这里就不笔记了。