Mathematische Funktionen
If you don't have/want GMP and are working with large numbers/currencies:
<?php
function mb_abs($number)
{
return str_replace('-','',$number);
}
?>
No need to worry about encoding, as your numbers should all be basic (ANSI) strings.
abs
(PHP 4, PHP 5)
abs — Absolutwert bzw. Betrag
Parameter-Liste
-
number -
Der zu bearbeitende Wert
Rückgabewerte
Der Betrag des Wertes number.
Ist number vom Typ float,
so ist auch das Ergebnis von diesem Typ, ansonsten wird
das Ergebnis als integer zurückgegeben
(da float einen größeren Wertebereich als
integer hat).
Beispiele
Beispiel #1 abs()-Beispiel
<?php
$abs = abs(-4.2); // $abs = 4.2; (double/float)
$abs2 = abs(5); // $abs2 = 5; (integer)
$abs3 = abs(-5); // $abs3 = 5; (integer)
?>
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User Contributed Notes
abs
svein dot tjonndal at gmail dot com
25-May-2011 12:44
Ister
17-Jul-2008 01:59
[*EDIT* by danbrown AT php DOT net: Merged user's corrected code with previous post content.]
jeremys indicated one thing - there is no sgn function wich actually seems a bit strange for me. Of course it is as simple as possible, but it is usefull and it is a standard math function needed occasionally.
Well, I have solved this function in a bit different matter:
<?php
function sgn($liczba)
{
if($liczba>0)
$liczba=1;
else if($liczba<0)
$liczba=-1;
else if(!is_numeric($liczba))
$liczba=null;
else
$liczba=0;
return $liczba;
}
?>
The difference is that it returns null when the argument isn't a number at all.
Josh
07-Jan-2006 04:06
Let's say you are resizing images to a standard size that can be expressed as a ratio (width/height). The problem I came into was that I wanted to be reasonable with the proportion of the images that my customer is uploading (couldn't we all use a little less horizontal on pictures?), but I wanted to reject the horizontal pictures when they were uploading vertical ones. So I wanted to accept proportions of images that were within a reasonable threshold (+ or -) of what I will be resizing them to.
Assuming a standard of 1 to 4 (0.25) and a threshold of no more than 0.05 deviation, then the number 0.30 and 0.20 would return true and 0.19 would return false.
<?php
function threshold($given,$thresh,$standard)
{
return (abs($given-$standard)<=$thresh) ? true : false;
}
?>