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### Re^2: list of four digit lock combinations without repeated digits

by Lotus1 (Vicar)
 on Jun 22, 2018 at 14:44 UTC ( #1217205=note: print w/replies, xml ) Need Help??

I did ask for interesting solutions. It's going to take me a while to understand how this works. I found in perlvar a description of @- as being an array of the indexes of the matches. Thanks for posting.

```@-
\$-[0] is the offset of the start of the last successful match. \$-[n] i
+s the offset of the start of the substring matched by n-th subpattern
+, or undef if the subpattern did not match.

Thus, after a match against \$_ , \$& coincides with substr \$_, \$-[0], \$
++[0] - \$-[0] . Similarly, \$n coincides with substr \$_, \$-[n], \$+[n] -
+ \$-[n] if \$-[n] is defined, and \$+ coincides with substr \$_, \$-[\$#-],
+ \$+[\$#-] - \$-[\$#-] . One can use \$#- to find the last matched subgrou
+p in the last successful match. Contrast with \$#+ , the number of sub
+groups in the regular expression. Compare with @+ .

This array holds the offsets of the beginnings of the last successful
+submatches in the currently active dynamic scope. \$-[0] is the offset
+ into the string of the beginning of the entire match. The nth elemen
+t of this array holds the offset of the nth submatch, so \$-[1] is the
+ offset where \$1 begins, \$-[2] the offset where \$2 begins, and so on.
[download]```

Replies are listed 'Best First'.
Re^3: list of four digit lock combinations without repeated digits
by tybalt89 (Parson) on Jun 22, 2018 at 22:45 UTC

Here's another version without the @-

Just match any four of the digits (from an ordered string).

```#!/usr/bin/perl

# https://perlmonks.org/?node_id=1217042

use strict;
use warnings;

'0123456789' =~ /(.).*?(.).*?(.).*?(.)(?{print "\$1\$2\$3\$4\n"})(*FAIL)/;
[download]```

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