RE: FILTER_VALIDATE_INT - newbie question

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On Wed, 2009-10-07 at 12:03 +0100, MEM wrote:
> > Well, it was only a guess, but if you look at the integer limit on 32-bit systems, you'll see that the upper limit > for numbers is 2147483647 (or 2^31-1) which would explain maybe your upper limit problem.
> >
> > Also, I think you're getting confused over the zero with exactly what you are asking PHP to do. filter_var() returns > true if the filter matches. If the 0 match is returned as a false, then filter_var() will return false. You're then > inverting that with a !, all of which is inside an if() statement. Essentially this would mean that if the filter > returns false then the instructions inside of the if statement are carried out.
> 
> 
> I always thought that that was a limit of the number of digits an integer value could have, and not the actually int value... I guess I was wrong. :s
> 
> You are right, I've tested with: 
> 2147483647 
> it worked.
> 
> I've tested with:
> 2147483648
> It displays the error.
> 
> "you're getting confused over the zero with exactly what you are asking PHP to do"
> Absolutely... :(
> 
> If I put 0 filter_var() will return false.
> If I put 0342352 filter_var() will also return false.
> 
> Could we say that: if it is indeed the fact, that filter_var() returns false when it finds a 0 at the beginning of a given number...
> 
> 	"then the instructions inside of the if statement are carried out."
> 
> And here may be the reason for displaying the error message when we have the 0 leading a number.
> 
> And my point was exactly here
> "If the 0 match is returned as a false" 
> 
> Why should filter_var() do something like this? Should the filter_var() interpretate 0 as a number without boolean semantic value?
> 
> 
> Please be patient... 
> Regards,
> Márcio
> 

Imho it shouldn't behave like this. 01 is equally as valid as 1 as far
as numbers go, we just ignore leading 0's on any number unless they are
in a significant position (i.e. 0.1)

I am also surprised to see that while it converts the value to an
integer, it doesn't seem to do that first, because 01 is a valid
integer:

<?php
$i = 0;
$j = 01;

var_dump($i);
var_dump($j);
?>

The output returns:

int(0)
int(1)

So the filter seems to be doing some form of check on leading zero's
before checking the validity of the number!

Thanks,
Ash
http://www.ashleysheridan.co.uk




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