Are you interested in the end product or do you want all intermediates?
This will give you the end product:
use feature 'say';
my $string = "12345";
$string = substr( $string, 1 ) . substr( $string, 0, 1 );
EDIT: Just realized you were asking for something else. Oops. I think AnomalousMonk is correct about it not being possible this way. Regarding the errors, you need to specify the second capture group since the second set of parentheses you have are part of the lookahead. This gets rid of the warnings:
$ perl -WE '$string = "12345"; $string =~ s/(.)(?=(.))/$2$1/g; say $st
Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
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:
You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
- a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, 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, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
Link using PerlMonks shortcuts! What shortcuts can I use for linking?
See Writeup Formatting Tips and other pages linked from there for more info.
| & || & |
| < || < |
| > || > |
| [ || [ |
| ] || ] ||