'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

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

Unable to display contents in Second Drop Down Box
Hi All,

What I am trying to do is 2 dependent drop down boxes and when user selects su

ALV List Display to point to another report on Double Click
Hi,

I want my ALV List Display to point to another report on Double Click on its line ite

Displaying values from a SQL count...
Hi,
Easy enough question i just forget the exact method ..
I have ...

Code: //count win

Calling All PHPFREAKS Blackberry Users
Are you a member of PHPFreaks and have a blackberry? Well RIM just recently released Blackberry Mes

CURL question
i am wondering if it's possible to use multi curl with login something like

login once to web

Wordpress IE issue
So I am trying to add the background shadow to my wordpress page. It works fine in Firefox but does

Material xxx does not exist in plant xxx
Dear All,

I am working for a steel project which is repetitive manufacturing.

Php Mysql Page Loading Notice
Hi all,

I was wondering if there is a way (Sure there is) of showing a message or an image wh

Passing JS to PHP
So I have the following
Code: <?php
getdetails(?><script type="text/