### Re: Multiple Combinatorics

by BrowserUk (Pope)
 on Apr 15, 2012 at 09:45 UTC ( #965145=note: print w/replies, xml ) Need Help??

```#! perl -slw
use strict;

sub nFor(&@) {
my \$code = shift;
die "First argument must be a code ref" unless ref( \$code ) eq 'CO
+DE';
my @limits = @_;

my @indices = ( 0 ) x @limits;

for( my \$i = \$#limits; \$i >= 0; ) {
\$i = \$#limits;
\$code->( @indices ), ++\$indices[ \$i ]
while \$indices[ \$i ] < \$limits[ \$i ];
\$i = \$#limits;
\$indices[ \$i ] = 0, ++\$indices[ --\$i ]
while \$i >= 0 and \$indices[ \$i ] == \$limits[ \$i ];
}
}

my @a = 'a'..'z';
my @a3;
nFor{
push @a3, [ @a[ @_ ] ];
} ( scalar @a ) x 3;

my @b = 0 .. 9;
my @b2;
nFor{
push @b2, [ @b[ @_ ] ];
} ( scalar @b ) x 2;

nFor {
print join '-', @{ \$a3[ \$_[0] ] }, @{ \$b2[ \$_[1] ] };
} scalar @a3, scalar @b2;

__END__
C:\test>965138 | wc -l
1757600

C:\test>965138
a-a-a-0-0
a-a-a-0-1
a-a-a-0-2
a-a-a-0-3
...
z-z-z-9-6
z-z-z-9-7
z-z-z-9-8
z-z-z-9-9

With the rise and rise of 'Social' network sites: 'Computers are making people easier to use everyday'
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In the absence of evidence, opinion is indistinguishable from prejudice.

The start of some sanity?

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