Really, I too was surprised. Changing sub test to 

sub test {
    my @rv = $_[0] =~ /^([0-9]+)$/;
    print "<<@rv>>\n";
    return @rv[ 0 .. $#rv ];
}

[download]
produced 
<<>>
[[]
<<>>
[]
<<123>>
[123]
<<123>>
[123]

[download]
changing sub test to 
sub test {
    my @rv = $_[0] =~ /^([0-9]+)$/;
    print "<<@rv>>\n";
    return wantarray? @rv: $rv[-1];
}

[download]
produces 
michael$ perl t.pl
<<>>
Use of uninitialized value in print at t.pl line 5.
[]
<<>>
[]
<<123>>
[123]
<<123>>
[123]

[download]
Note the warning. (And I suspect there are some monks who are now saying I told you so;-)

In reply to Re^3: regexp list return 5.6 vs 5.8 by hipowls
in thread regexp list return 5.6 vs 5.8 by Sixtease

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.