i suppose it depends on how you define almost sorted data. you're right about the example i provided (silly me.) but, if the list contains a few swapped elements, bubble is fast, fast, fast.

enough about that. your code is broken. it only performs one pass through the data, so it will only sort one element. try something like: Update: i need to eat breakfast before i post any more... and i prefer the sort all in one sub, so here's mine (lifted from mastering algorithms, if i recall correctly:)

sub bubble
{
    my @array = @{ $_[0] };
    for( my $i = $#array; $i; $i-- )
    {
        for( my $j = 1; $j <= $i; $j++ )
        {
            @array[$j, $j-1] = @array[$j-1, $j] 
                if( $array[$j-1] > $array[$j] );
        }
    }
    return \@array;
}
my $aRef = [ 2, 4, 3, 5, 1 ];
my $aSortedRef = bubble( $aRef );

print "@{$aRef}$/";
print "@{$aSortedRef}$/";
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which iterates through the array backwards (the sorted data gathers on the tail end) and swaps elements until they're ordered.

also, your code sorts data in-place. i modified it to sort to a new array, as it's my preference.

~Particle ;Þ