On Thu, 2009-10-29 at 17:30 -0400, Andre Walker-Loud wrote:
> I have a simple question. I am writing a little program that will
> make some plots of data files. I want to have optional args to pass,
> for example to specify the plot ranges. I have never written a script/
> code that takes optional args (but I have used plenty) - so I am
> feeling a little sluggish writing a good sys.argv reader. I have the
> following few lines I made, but I am wondering if any of you have
> suggestions for how to make this better (ie more slick, more readable,
> more general etc)
You are a perfect candidate for the optparse module [1] which will do
the heavy lifting for you.
Example code relating to your code below.
------
>>> from optparse import OptionParser
>>> parser = OptionParser()
>>> parser.add_option('-f', '--file', action='store', type='string',
dest='filename', help='Explain your filename')
<Option at 0x20cf7e8: -f/--file>
>>> parser.add_option('-x', action='store', type='int', dest='x',
help='Explain your x value')
<Option at 0x20cf998: -x>
>>> parser.print_help()
Usage: [options]
Options:
-h, --help show this help message and exit
-f FILENAME, --file=FILENAME
Explain your filename
-x X Explain your x value
>>>
>>> args = ['-f','somefilename','-x', '25']
>>> opts, args = parser.parse_args(args)
>>> opts.x
25
>>> opts.filename
'somefilename'
>>> type(opts.x)
<type 'int'>
-----
Greets
Sander
[1] http://docs.python.org/library/optparse.html
> import sys
>
> if len(sys.argv) < 2:
> print('no data file specified')
> sys.exit(-1)
> elif len(sys.argv) > 2:
> if sys.argv.count('-x') > 1:
> print('error: multiple instances of "-x xmin xmax"')
> sys.exit(-1)
> elif sys.argv.count('-x') == 1:
> xrange = sys.argv.index('-x')
> if sys.argv.count('-y') > 1:
> print('error: multiple instances of "-y ymin ymax"')
> sys.exit(-1)
> elif sys.argv.count('-y') == 1:
> yrange = sys.argv.index('-y')
> else:
> xrange = 0
> yrange = 0
>
> if xrange != 0:
> xmin = float(sys.argv[xrange+1])
> xmax = float(sys.argv[xrange+2])
> else:
> xmin = "x-min determined from data file"
> xmax = "x-max determined from data file"
>
> if yrange != 0:
> ymin = float(sys.argv[yrange+1])
> ymax = float(sys.argv[yrange+2])
> else:
> ymin = "y-min determined from data file"
> ymax = "y-max determined from data file"
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