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Date: Tue, 24 Jul 2012 10:01:48 +0200
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Subject: Working with floats
From: robin@kingsquare.nl ("Kingsquare.nl - Robin Speekenbrink")

Hi all,

First of all, let me state that the following question is probably going 
to shun me forever due to the 'basic' nature of the question and the 
probable misunderstanding of floats in general, but still this got me 
baffled and i'd like to post this here:

Why does the last of the following examples lower my key to 18 BUT does 
the var dump of the float clearly state 'float(19)' as the actual value:
<?php
$i = (float)19;
var_dump($i);
$arr = array($i=>1);
var_dump($arr);

$i = (float)19.000000000000000000;
var_dump($i);
$arr = array($i=>1);
var_dump($arr);

$i = (float)18.99999999999999999;
var_dump($i);
$arr = array($i=>1);
var_dump($arr);

$i =(float) .19;
$i *= 100;
var_dump($i);
$arr = array($i=>1);
var_dump($arr);

$i =(float) 0.19;
$i *= 100;
var_dump($i);
$arr = array($i=>1);
var_dump($arr);

$i =(float) 1.19;
$i -= 1;
$i *= 100;
var_dump($i);
$arr = array($i=>1);
var_dump($arr);
?>

I do know this is not really an internals thing, but after fiddling with 
this for some time, i gave up (bug 32671 might relate to this)

Again, if i'm to be regarded as a traditional n00b, i understand as i've 
seen float / casting discussions before.