Re: How to not print the same random number

The following should achieve pretty random results within the constraints you asked for - 10 unique numbers from 1-10 sorted randomly.

@arr = 1..10;
randomize(\@arr);

print "@arr";

sub randomize {
    my ($p, $size, $swap, $key);
    $p = $_[0];

    $size = $#$p;
    for (0..($size-1)) {
        $swap = int rand($size - $_ + 1) + $_;
        $key = $p->[$_];
        $p->[$_] = $p->[$swap];
        $p->[$swap] = $key;
    }
}
[download]

Comment on Re: How to not print the same random number Download Code

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Re^2: How to not print the same random number by GrandFather (Saint) on Mar 05, 2006 at 21:17 UTC
You can eliminate the manifest temporary by: `($p->[$_], $p->[$swap]) = ($p->[$swap], $p->[$_]);` [download] Note though that it is slower: `use strict; use warnings; use Benchmark qw(cmpthese); my @arr = 1..2; cmpthese (-1, { temp => sub {my $temp = $arr[0]; $arr[0] = $arr[1]; $arr[1 +] = $temp;}, swap => sub {($arr[0], $arr[1]) = ($arr[1], $arr[0]);}, } ); Rate swap temp swap 1381331/s -- -43% temp 2425611/s 76% --` [download] DWIM is Perl's answer to Gödel	[reply] [d/l] [select]
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Re^2: How to not print the same random number
by GrandFather (Saint) on Mar 05, 2006 at 21:17 UTC

You can eliminate the manifest temporary by:

($p->[$_], $p->[$swap]) = ($p->[$swap], $p->[$_]);
[download]

Note though that it is slower:

use strict;
use warnings;
use Benchmark qw(cmpthese);

my @arr = 1..2;

cmpthese (-1,
            {
            temp => sub {my $temp = $arr[0]; $arr[0] = $arr[1]; $arr[1
+] = $temp;},
            swap => sub {($arr[0], $arr[1]) = ($arr[1], $arr[0]);},
            }
         );

          Rate swap temp
swap 1381331/s   -- -43%
temp 2425611/s  76%   --
[download]

DWIM is Perl's answer to Gödel

[reply]
[d/l]
[select]

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