Inserting '-' character in front of all numbers in a string

Larry Bates larry.bates at
Fri Mar 30 17:55:08 CEST 2007

kevinliu23 wrote:
> Hey guys,
> I want to be able to insert a '-' character in front of all numeric
> values in a string. I want to insert the '-' character to use in
> conjunction with the getopt.getopt() function.
> Rigt now, I'm implementing a menu system where users will be able to
> select a set of options like "2a 3ab" which corresponds to menu
> choices. However, with getopt.getopt(), it'll only return what I want
> if I input -2a -3ab as my string. I don't want the user have to insert
> a '-' character in front of all their choices, so I was thinking of
> accepting the string input first, then adding in the '-' character
> myself.
> So my qusetion is, how do I change:
> "2a 3ab" into "-2a -3ab".
> Regular expressions? :/
s="2a 3b"
s="-%s -%s"% tuple(s.split())


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