Re: list of four digit lock combinations without repeated digits

A solution using glob to generate the 4-digit numbers, split, sort and join to get only ascending values then grep and a regex to sift out repeating digits. A hash is populated so that any duplicate values go into the same key/value pair and are therefore masked. Finally print the sorted values.

johngg@abouriou ~/perl/Monks $ perl -Mstrict -Mwarnings -E '
my $digs    = q{0,1,2,3,4,5,6,7,8,9};
my $globStr = qq|{$digs}| x 4;
my %combs   =
   map  { $_ => 1 }
   grep { ! m{(.).*\1} }
   map  { join q{}, sort split m{} }
   glob $globStr;
say for sort keys %combs;' | wc -l
210
[download]

I hope this is of interest.

Update: Can be shortened by acting directly on an anonymous hash but there's a warning unless you silence it (which, sadly, makes it not so short again).

johngg@abouriou ~/perl/Monks $ perl -Mstrict -Mwarnings -E '
my $digs    = q{0,1,2,3,4,5,6,7,8,9};
my $globStr = qq|{$digs}| x 4;
say for do {
   no warnings qw{ experimental::autoderef };
   sort keys {
   map  { $_ => 1 }
   grep { ! m{(.).*\1} }
   map  { join q{}, sort split m{} }
   glob $globStr };
   };' | wc -l
210
[download]

Cheers,

JohnGG

Comment on Re: list of four digit lock combinations without repeated digits Select or Download Code

Replies are listed 'Best First'.

Re^2: list of four digit lock combinations without repeated digits
by Lotus1 (Vicar) on Jun 22, 2018 at 14:58 UTC

I tried out your glob approach at number generation to understand it. Thanks for posting. I'm always trying to learn more about the usage of glob(). I found I could simplify your $globStr declaration like this:

use warnings;
use strict;

my $digit_pattern = '{0,1,2,3,4,5,6,7,8,9}' x 4;
print "$_\n" foreach glob $digit_pattern;
[download]

When I saw your solution I realized I didn't need to test for the key existence in the hash. I could simply assign to the key. Thanks again.

Edit:

   sort keys {
   map  { $_ => 1 }
   grep { ! m{(.).*\1} }
   map  { join q{}, sort split m{} }
   glob $globStr };
[download]

[reply]
[d/l]
[select]


Problems? Is your data what you think it is?
	PerlMonks