Pythonically extract data from a list of tuples (getopt)

[Mark Reed]

So the return value from getopt.getopt() is a list of tuples, e.g.

>>import getopt
>>opts = getopt.getopt('-a 1 -b 2 -a 3'.split(), 'a:b:')[0]; opts

[('-a', '1'), ('-b', '2'), ('-a', '3')]

what's the idiomatic way of using this result? I can think of several
possibilities.

For options not allowed to occur more than once, you can turn it into
a dictionary:

>>b = dict(opts)['-b']; b

'2'

Otherwise, you can use a list comprehension:

>>a = [arg for opt, arg in opts if opt == '-a']; a

['1', '3']

Maybe the usual idiom is to iterate through the list rather than using
it in situ...

>>a = []
>>b = None
>>for opt, arg in opts:

.... if opt == '-a':
.... a.append(arg)
.... elif opt == '-b':
.... b = arg
.... else:
.... raise ValueError("Unr ecognized option %s" % opt)

Any of the foregoing constitute The One Way To Do It? Any simpler,
legible shortcuts?

Thanks.

[Mike Kent]

Re: Pythonically extract data from a list of tuples (getopt)

You could use http://docs.python.org/lib/module-optparse.html