'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
Did you know?Explore Trending and Topic pages for more stories like this.
$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
No comments posted yet

Your Answer:

Login to answer
199 Like 53 Dislike
Previous forums Next forums
Other forums

Create PHP table grid help, please
I have a MySQL database setup, now it's time for the table (gridview) design in php. Here's the prob

Secure pages Sessions vs. Cookies & session_destroy() help
Im new here and new to PHP, I hope you can help me with some questions.

Im writing my web ap

Production Order Enterprise Service to Manufacturing Exctn Sys (MES) ???
Hello Experts,

In our current landscape SAP ECC 5.0 is integrated to MES system via PI 7.

Using Curl_multi for processing multiple URLs
Hi,

I am at a loss as to how to implement this. I would like to be able to automatically assi

Two warning messages
Quote<b>Warning</b>: mysql_real_escape_string() expects parameter 1 to

COOIS - Saving Object Overview WIP Status layouts
COOIS - Would like to be able to save the layout of an Object Overview - WIP Status report. There i

contact form - output to page and email
I have the following in my controller:

$message['name'] = htmlentities(strip_tags(trim($_POST

DB2 for z/OS, LUW, iSeries
Hello, In this forum a lot of threads related to other members of the DB2 family than DB2 for z/OS

Casting Decimals in Oracle
This code worked as a query in DB2, but I am not sure what the syntax is for casting decimals in Ora

Not sure why this script is not working?
Hi I am new to php programing and I was trying to make up a simple script like a captcha but I canno

Sign up to write
Sign up now if you have flare of writing..
Login   |   Register
Follow Us
Indyaspeak @ Facebook Indyaspeak @ Twitter Indyaspeak @ Pinterest RSS



Play Free Quiz and Win Cash