'210010106140040100' == '210010106140040101'

Posted on 16th Feb 2014 07:03 pm by admin

Debugging this simple line of a PHP script

Code: if($a == $b){ }
I've found that with value of
$a = '210010106140040100' (type = string)
$b = '210010106140040101' (type = string)

the result of the comparison is TRUE

the same if i compare 2 integer

$a = 210010106140040100 (type = int)
$b = 210010106140040101 (type = int)

$a == $b ( true )

If I use the === operator

'210010106140040100' === '210010106140040101' (comparison of strings: result is FALSE)
210010106140040100 === 210010106140040101 (comparison of numbers: result is TRUE)

I think it could be caused by the fact that the string is 'like' integer, but exceed the standard size of integer number.
But the final result remain a mistery for me: I've tested some others 'big' numbers and I've found for example:

18014398509481980==18014398509481981 (true) !!!!
18014398509481982==18014398509481981 (false) !!!!

In my specific script i can handle this specific comparison using the === operator, because i can assume that the variable are string.

But i'd like to know why this happen, and i'd appreciate suggestions about how to efficiently compare 'big' integers.

Thanks!

I use PHP 5.2 with IIS

Your Answer:

Login to answer

Other forums

Login logout link help
Hi all,

Im new to php and Im having trouble creating a login/logout link for my page that dis

PHP Include not working
The website is http://www.grlistingservices.com

The code block is as follows:

<

What am I missing here? Help!
Hello all!. I can't seem to get this working right. Well - it renders right, but something is goin

writing my own sobel filter convolution - something is wrong
I am trying to keep it very simple, I cant see anything wrong with my logic, could anybody help poin

form variables from database help.
Hi all,

I would like to have a form that gives you options based on the results of an mysql q

List/Menu Box
On an edit page when you want something to select what a user has previously selected from the datab

Inserting into MySQL Newbie
Hi ive got a slight problem where ive made a simple web form where the customer inserts the ammount

Storing/displaying image urls in a database?
Hi
Basically I have the following scenario:
User chooses picture from list. Picture info is ad

Can anyone give me some link on .htaccess tutorial
i wish to have friendly url using .htaccess, but no idea yet about this

Hope that anyone cou

grouping within a foreach?
hello all,

I currently have a list of products spit out from my db via a foreach loop. Right