$s = 'abc 1 23 do 456 re 789 me 0123 456 2 23 456 789 0123 456';

push @results, ("This has " . length($1) . " digits: $1") 
                while $s =~ /(\d+)/g;
print "$_\n" for @results;

# Prints:
# This has 1 digits: 1
# This has 2 digits: 23
# This has 3 digits: 456
# This has 3 digits: 789, etc.

##</code><code>##

$s = '1 23 456 789 0123 456 2 23 456 789 0123 456';

push @results, ("This looks like a word: $1") while $s =~ /((?:\b\d{1,2}\s+)+\b\d{3,})/g;
print "$_\n" for @results;

# Prints:
# This looks like a word: 1 23 456
# This looks like a word: 2 23 456