http://www.perlmonks.org?node_id=774325


in reply to String manipulation

Something like this may do the job:

use strict;
use warnings;
use feature qw/ :5.10 /;

my @str = ("j    k l         foobar", "foobar", "jkl foobar", "1 2 3",
+ "jk l foobar", "foobar j k l", "foobar j kl", "           ", " ", "j
+ jk foobar", "j k jk foobar", "j k l");

my $rx = qr/^((?:\w(?:\s+|\z))*)(.*)/;

for my $str (@str){
  my ($i,$s) = $str =~ /$rx/;
  $i =~ s/\s+//g;
  say $i ? join " ",$i,$s : $s;
}

[download]

Outputs:

jkl foobar
foobar
jkl foobar
123
jk l foobar
foobar j k l
foobar j kl


j jk foobar
jk jk foobar
jkl

[download]

citromatik

Replies are listed 'Best First'.
Re^2: String manipulation
by abhy (Novice) on Jun 24, 2009 at 10:42 UTC
    If I am not asking for too much, can you please expand the regex with comments?
[reply]

      Sure:

      my $rx = qr/
             ^            # At the beginning of the string  
             (            # Capture in $1
               (?:        # Paren for grouping (don't capture in $2)
                 \w       # match a "wordy" character
                 (?:      # paren for grouping,
                   \s+|\z # match at least one space or the end of the
+ string
                 )
               )*         # zero or more times
              )           # end of capture $1
            (.*)          # and match what comes after storing it in $
+2
          /x              # allow these comments
;

      [download]

      The rationale is to match at the beginning all the one-character strings, storing them in $1. The rest of the input will be catched in $2

      citromatik

[reply]
[d/l]
      abhy,
      If you don't know about YAPE::Regex::Explain, it is worth a look. I don't think it has been updated to take into consideration the new regex doodads in Perl 5.10 but it should be helpful regardless.

      Cheers - L~R

[reply]

In Section Seekers of Perl Wisdom