On Mon, January 23, 2006 6:53 pm, Matt Palermo wrote:
> I'm try to sort a list of items using a usort function. Basically, I
> want
> it to sort in this order:
>
> Numbers (0-9)
> Letters (Aa-Zz)
> Other (anything else)
>
> To explain a little further, I want anything that starts with a number
> to
> show up first in the sorted list, then anything that starts with a
> letter,
> and finally anything that starts with some other character. My usort
> function I'm using now gives me results close to this, but it sorts it
> as
> follows (which is wrong for what I need):
>
> Numbers (0-9)
> Other (anything else)
> Letters (Aa-Zz)
>
> They are all sorted properly alphabetically, but not in the group
> order that
> I need them in. Here is the usort function I'm using right now:
>
>
> function myUsort($x, $y)
> {
> if(strtolower($x) == strtolower($y)) return 0;
> if(strtolower($x) < strtolower($y)) return -1;
> return 1;
> }
The issue with previous posts is that they will only look at the first
character, unless I'm mis-reading them.
So:
__a
_a_
will not sort the way you want.
Here is my take on it:
function myUsort($x, $y){
//ignore case (I chose upper only because I know the ASCII values)
$x = strtoupper($x);
$y = strtoupper($y);
$xlen = strlen($x);
$ylen = strlen($y);
$len = min($xlen, $ylen);
for ($i = 0; $i < $len; $i++){
$xi = $x[$i]; $yi = $y[$i];
$xc = ord($xi); $yc = ord($yi);
if ($xi == $yi) continue;
//handle a-z and 0-9 normally:
elseif ( (65 <= $xc && $xc <=90 || 48 <= $xc && $xc <= 57)
&& (65 <= $yc && $yc < 90 || 48 <= $yc && $yc <= 57)
)
return strcasecmp($xc, $yc);
//either $xi or $yi is out of the normal range and is "big"...
//$xc is the oddball character
elseif ($xc < 48 || $xc > 57 && $xc < 65 || $xc > 90) return 1;
//$yc must be the oddball character
else return -1;
}
//The strings completely matched, up to the end of one of them:
if ($xlen < $ylen) return -1;
elseif ($xlen > $ylen) return 1;
else return 0;
}
I'm not promising I got the -1 / 1 / 0 ordering correct for < > == but
this should work.
Probably not the fastest, particularly for long strings, as PHP for
loops are not speedy...
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