$placeholder = $date[$n];
$date[$n] = $date[$n2];
$date[$n2] = $placeholder;

##</code><code>##

($date[$n], $date[$n2])=($date[$n2], $date[$n]);

##</code><code>##

my @foo;
$foo[0]=0;
$foo[1]=1;
print "@foo\n";
($foo[0], $foo[1])=($foo[1], $foo[0]);
print "@foo\n";