in reply to compare two strings and return only he unique values.

#!/usr/bin/perl -w 

use strict;
use warnings;
my $string1="abcdef";
my $string2="defghi";

my @ary=split(//,$string1);
push @ary,split(//,$string2);
my %een=();

map{ $een{$_}++ } @ary;
my @unique=();
foreach (@ary){
    next unless $een{$_} == 1;
    push @unique,$_;
}

printf "%s\n",join(",",@unique);

[download]
Hashes are our friends....

Peter L. Berghold -- Unix Professional
Peter -at- Berghold -dot- Net; AOL IM redcowdawg Yahoo IM: blue_cowdawg

Replies are listed 'Best First'.
Re^2: compare two strings and return only he unique values.
by Kenosis (Priest) on Feb 03, 2013 at 21:24 UTC

    Won't show "a" when:

    my $string1="abcdefa";
my $string2="defghi";

    [download]
[reply]
[d/l]
          Won't show "a" when:

      That's because "a" isn't unique. :) 

      printf "%s\n",join(",", keys %een);

      [download]
      would show "a" and all the other letters once.

      Peter L. Berghold -- Unix Professional
      Peter -at- Berghold -dot- Net; AOL IM redcowdawg Yahoo IM: blue_cowdawg
[reply]
[d/l]

        Your code quite effectively forms a union of the two strings' characters. However, the OP's request was to 1) compare two strings, and 2) return only the unique values. Where does your code compare the two strings? Forming a union of their characters does not compare the two strings. In fact, if we strictly regard their union as a non-multiset of characters, "a" is unique, since (set notation): {a} = {a,a} = {a,a,a}. Thus, "a" should still appear in their union--even with two occurrences within one string.

        As has been point out, the OP's specs are equivocal, yet I tend to favor "unique" as meaning a character (replicated or not) that only belongs to one or the other string (i.e., "unique to")--and is not in both.

[reply]

In Section Seekers of Perl Wisdom