Re^2: regular expressions

[AnomalousMonk]

... the regex syntax to match 4 or more is not quite right. {4,} should be {4,}?. The first version would just match 4 at a minimum, but no more.

The quantifier  {4,} will match as much as possible (while still allowing an overall match), but at least four of the quantified atom. The quantifier  (4,}? will match as little as necessary for an overall match, but at least four of the quantified atom.

c:\@Work\Perl\monks>perl -wMstrict -le
"my @strings = qw(vw vwx vwxz vwxzp vwxzpd vwxzpdq);
 ;;
 my $consonant = qr{ [bBcCdDfFgGhHjJkKlLmMnNpPqQrRsStTvVwWxXzZ] }xms;
 ;;
 for my $s (@strings) {
   print qq{'$s'};
   print qq{{4,} matched; captured '$1'}  if $s =~ m{ ($consonant{4,} 
+) }xms;
   print qq{{4,}? matched; captured '$1'} if $s =~ m{ ($consonant{4,}?
+) }xms;
   print '';
   }
"
'vw'

'vwx'

'vwxz'
{4,} matched; captured 'vwxz'
{4,}? matched; captured 'vwxz'

'vwxzp'
{4,} matched; captured 'vwxzp'
{4,}? matched; captured 'vwxz'

'vwxzpd'
{4,} matched; captured 'vwxzpd'
{4,}? matched; captured 'vwxz'

'vwxzpdq'
{4,} matched; captured 'vwxzpdq'
{4,}? matched; captured 'vwxz'

See perlre, perlretut, and perlrequick.