On 28/02/2008, Robert Cummings <robert@xxxxxxxxxxxxx> wrote:
>
> On Thu, 2008-02-28 at 12:39 +0000, Nathan Rixham wrote:
> > Aschwin Wesselius wrote:
> > > Stut wrote:
> > >> Just because it works doesn't mean it's right.
> > >>
> > >> -Stut
> > >>
> > >
> > >
> > > What I meant was that I tested the script and it worked, so I didn't
> > > spot the flaw (wich is obvious and you were right).
> > >
> > > No big deal.
> > >
> >
> > should it not use curlies?
> >
> > $tmp = '';
> > $str = 'abcdef';
> > for ($i = strlen($str)-1; $i >= 0; $i--) {
> > $tmp.= $str{$i};
> > }
> > echo $tmp;
> >
> >
> > here's the "overkill" way to do it:
> >
> > $str = 'abcdef';
> > $rev = implode(array_flip(array_reverse(array_flip(str_split($str)))));
> > echo $rev;
> >
> > *sniggers*
>
>
> There's always a tradeoff between speed and memory. Here's the low
> memory version:
>
> <?php
>
> $str = '1234567';
> str_reverse_in_place( $str );
> echo 'Reversed: '.$str."\n";
>
> function str_reverse_in_place( &$str )
> {
> $a = 0;
> $z = strlen( $str ) - 1;
>
> while( $a < $z )
> {
> $t = $str[$a];
> $str[$a] = $str[$z];
> $str[$z] = $t;
>
> ++$a;
> --$z;
> }
> }
>
> ?>
every byte counts :-)
function str_reverse_in_place( &$str )
{
$a = -1;
$z = strlen($str);
while( ++$a < --$z )
{
$str[$a] = $str[$a] ^ $str[$z];
$str[$z] = $str[$a] ^ $str[$z];
$str[$a] = $str[$a] ^ $str[$z];
}
}
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