Matching two overlapping patterns with Perl

Question

I hope that my question has not already been posed by someone else, since I tried to look almost everywhere in the site but I couldn\'t manage to find an answer.

My

Answer 1

You have to use looakahead and count the number of matches

(?=beta|alpha)

Not tested in perl but should work

works here

Answer 2

The following uses a zero-width assertion (I believe that's what it's called).

#!/usr/bin/perl
use strict;
use warnings;

$_ = "betalphabetabeta";

while (/(?=(alpha|beta))/g) {
    print $1, "\n"; 

Prints:

C:\Old_Data\perlp>perl t9.pl
beta
alpha
beta
beta