command line args

[Steven Bethard]

joe at gmail.com wrote:
> Hello,
> 
> I have the following commands:
> testb -s <size>
> testb -s <size> -o <input file>
> testb -s <size> -o <codes>
> 
> How do i split the commands so that all three are valid. And how do i
> check for missing arguments?  

Use optparse.  It's an improvement over the old getopt that makes 
writing option parsers easy:

py> import optparse
py> option_parser = optparse.OptionParser(
...     usage='%prog -s <size> [-o <input file|codes>]')
py> option_parser.add_option('-s', metavar='<size>', type='int')
<Option at 0x12b1ee0: -s>
py> option_parser.add_option('-o', metavar='<input file|codes>')
<Option at 0x12b1fd0: -o>
py> options, args = option_parser.parse_args('-s 1 -o data.txt'.split())
py> options.s, options.o
(1, 'data.txt')
py> option_parser.print_help()
usage: evaluation.py -s <size> [-o <input file|codes>]

options:
   -h, --help            show this help message and exit
   -s <size>
   -o <input file|codes>

STeVe