Re: RE: Quantifiers in regular expressions

[ninja-joe]

Here's a simple modification to the example code that will show what the regex matched when you typed it in:

#!/usr/bin/perl
while(<>) {
     chomp; # chomp so this next output is pretty.
            # newlines aren't discarded when you <>
     print "\"$1\" was matched out of \"$_\"" if m/(your_pattern)/;
}

Be sure to include the parenthesis around the entire regex that way it will save what it matches in $1.

Do recall that while the regex operators are greedy by default you can suffix them with ? and they'll go to nongreedy. An example:

#!/usr/bin/perl

while(<>) {
        chomp;
        print "\"$1\" was matched out of \"$_\"\n" if m/(\w{5}?)/;
}

This will match "mywor" out of "myword"

Have fun regexing.

[Roy Johnson]

Putting a ? on a quantifier that isn't variable-length is like having any color car you want, as long as it's black. There's no difference between a greedy and a non-greedy {5}.

A greedy quantifier will take as many characters as it can, and then start backtracking until whatever follows it matches. A non-greedy one will take as few characters as it can, and then take more until whatever is supposed to follow it is found.