Regular expression to search for Gadaffi

Question

I\'m trying to search for the word Gadaffi. What\'s the best regular expression to search for this?

My best attempt so far is:

\\b[KG]h?add?af?fi$\\         


        

Answer 1

Using CPAN module Regexp::Assemble:

#!/usr/bin/env perl

use Regexp::Assemble;

my $ra = Regexp::Assemble->new;
$ra->add($_) for qw(Gadaffi Gadafi Gadafy Gaddafi Gaddafy
                    Gaddhafi Gadhafi Gathafi Ghadaffi Ghadafi
                    Ghaddafi Ghaddafy Gheddafi Kadaffi Kadafi
                    Kaddafi Kadhafi Kazzafi Khadaffy Khadafy
                    Khaddafi Qadafi Qaddafi Qadhafi Qadhdhafi
                    Qadthafi Qathafi Quathafi Qudhafi Kad'afi);
say $ra->re;

This produces the following regular expression:

(?-xism:(?:G(?:a(?:d(?:d(?:af[iy]|hafi)|af(?:f?i|y)|hafi)|thafi)|h(?:ad(?:daf[iy]|af?fi)|eddafi))|K(?:a(?:d(?:['dh]a|af?)|zza)fi|had(?:af?fy|dafi))|Q(?:a(?:d(?:(?:(?:hd)?|t)h|d)?|th)|u(?:at|d)h)afi))

Answer 2

Well since you are matching small words why don't you try a similarity search engine with the Levenshtein distance? You can allow at most k insertions or deletions. This way you can change the distance function to other things that work better for your specific problem. There are many functions available in the simMetrics library.

Answer 3

If you want to avoid matching things that no-one has used (ie avoid tending towards ".+") your best approach would be to create a regular expression that's just all the alternatives (eg. (Qadafi|Kadafi|...)) then compile that to a DFA, and then convert the DFA back into a regular expression. Assuming a moderately sensible implementation that would give you a "compressed" regular expression that's guaranteed not to contain unexpected variants.