in reply to randomize array

If you are expecting the statement 
 @$array[$i,$j] = @$array[$j,$i];

[download]
to interchange the elements, you are missing a step or two. You need to do something like: 
 my $temp =  $array->[$i,$j];
 $array->[$i,$j] = $array->[$j,$i];
 $array->[$j,$i] = $temp;

[download]
Update:I stand corrected - Thanks, Thelonius. Please Ignore this node. <Feeble_excuse>Late night brain block did not process the array-ref-slice syntax correctly</Feeble_excuse>.

     "For every complex problem, there is a simple answer ... and it is wrong." --H.L. Mencken

Replies are listed 'Best First'.
Re^2: randomize array
by Thelonius (Priest) on Mar 29, 2006 at 06:31 UTC
    If you are expecting the statement ... to interchange the elements, you are missing a step or two.
    No, that part works fine:
    my @usernames = qw(zero one two three four five six);
testswap(\@usernames);
print join(" ", @usernames), "\n";

sub testswap {
 my $array = shift;
 my $i = 2;
 my $j = 5;
 @$array[$i, $j] = @$array[$j, $i];
}

    [download]
    Prints: zero one five three four two six

    As runrig pointed out, you're not returing a value, you could put return $array->[0] at the end of the subroutine.

    If you just want to pick one element out of the list, you're going to too much trouble. You can just say:

    my $username = $usernames[rand(@usernames)];

    [download]
[reply]
[d/l]
[select]

In Section Seekers of Perl Wisdom