Is there anyway to persuade python's getopt to handle optional paramters to options?

Question

According to the documentation on python's getopt (I think) the options fields should behave as the getopt() function. However I can't seem to enable optional parameters to my code:

#!/usr/bin/python
import sys,getopt

if __name__ == "__main__":
    try:
        opts, args = getopt.gnu_getopt(sys.argv[1:], "v::", ["verbose="])
    except getopt.GetoptError, err:
        print str(err)
        sys.exit(1)

    for o,a in opts:
        if o in ("-v", "--verbose"):
            if a:
                verbose=int(a)
            else:
                verbose=1
            print "verbosity is %d" % (verbose)

Results in:

$ ./testopt.py -v
option -v requires argument
$ ./testopt.py -v 1
verbosity is 1

Answer 1

getopt doesn't support optional parameters. in case of long option you could do:

$ ./testopt.py --verbose=

which will result in empty-string value.

You could find argparse module to be more flexible.

Answer 2

Unfortunately, there is no way. From the optparse docs:

Typically, a given option either takes an argument or it doesn’t. Lots of people want an “optional option arguments” feature, meaning that some options will take an argument if they see it, and won’t if they don’t. This is somewhat controversial, because it makes parsing ambiguous: if "-a" takes an optional argument and "-b" is another option entirely, how do we interpret "-ab"? Because of this ambiguity, optparse does not support this feature.

EDIT: oops, that is for the optparse module not the getopt module, but the reasoning why neither module has "optional option arguments" is the same for both.

Answer 3

If you're using version 2.3 or later, you may want to try the optparse module instead, as it is "more convenient, flexible, and powerful ...", as well as newer. Alas, as Pynt answered, it doesn't seem possible to get exactly what you want.