[Tutor] Redux: optparse

[Kent Johnson]

On Sat, Dec 27, 2008 at 2:55 PM, Matt Herzog <msh at blisses.org> wrote:
> What I can't figure out now is how to pass a compiled regex to an optparse option. I'm confused ias to "option" versus "arg" when using the optparse module. In fact there seems to be no way to define what the arg should be; only options. Is the arg always implied? I have read several pages on optparse and am none the wiser.

You want to *retrieve* the regex from the option, not pass it to the
option. See below.

"args" is the positional arguments - any parameters that aren't
prefixed with a switch like "-x". They don't need any configuration.

> How do I fix the rx = re.compile('-x') line below so that the string I pass on the command line gets passed into the re.compile?
>
> #!/usr/bin/python
> import fileinput, sys, string, optparse, re
>
> #def main():
> optparser = optparse.OptionParser()
> optparser.add_option("-x", "--regx", help="regular expression")
> # take the first argument out of sys.argv and assign it to searchterm
> #searchterm, sys.argv[1:] = sys.argv[1], sys.argv[2:]
> (options, args) = optparser.parse_args()
>
> rx = re.compile('-x')

Try
  rx = re.compile(options.regx)

Kent