Here's a substution-based version that may be somewhat along the lines Learnlot1 was thinking of originally. It does not generalize well to handling more than two strings as the split-to-hash approaches do. It suffers from the vagueness of the implied specification as other approaches do. But it works (for some definition of 'works'). 

>perl -wMstrict -le
"for my $ar_vector (
   [ qw(ABCDE BCDEO) ], [ qw(ABCDE BBBBB) ], [ qw(ABCDEA BCDEO) ],
   ) {
   my ($s1, $s2) = @$ar_vector;
   printf qq{'$s1' '$s2' -> '%s' \n}, non_common($s1, $s2);
   }
 ;;
 sub non_common {
   my ($sa, $sb) = @_;
   ;;
   (my $a_sans_b = $sa) =~ s{ [\Q$sb\E]+ }{}xmsg;
   (my $b_sans_a = $sb) =~ s{ [\Q$sa\E]+ }{}xmsg;
   return $a_sans_b . $b_sans_a;
   }
"
'ABCDE' 'BCDEO' -> 'AO'
'ABCDE' 'BBBBB' -> 'ACDE'
'ABCDEA' 'BCDEO' -> 'AAO'

[download]

In reply to Re: compare two strings and return only he unique values. by AnomalousMonk
in thread compare two strings and return only he unique values. by Learnlot1

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.