'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

PHP MySQL Return Results Issue
Hi guys,

I'm running joomla and made a module which is using ajax.
Basically i just have a

Deleting a record php
Attempting to setup delete a record page. The below code I put together doesn't seem to work.

phpmailer class & pop.gmail.com?
Code: <?php
$mail->IsSMTP();
$mail->Host = "pop.gmail.com";

Session login issue
I'm wondering how to fix a problem I'm having with a session-based login system

Say I go to h

Changing files over
Just thought I'd start with the new forums looking really nice .

Ok basically I've made this

RadioButtonList data selection
view plaincopy to clipboardprint?

How to find OS bit version
How can I tell the person browsing my site is running 32, or 64 bit operating system?

Multidimensional $_POST
Hello

How to get a single array from array of array (2 - dimension).
For example I have a

IS Retail & Manufacturing
Hi

Can IS Retail and Manufacturing activities be done in same instance ie. in same client

Include a php
Hello,

I'm trying to include a function that shows the recent searches.
Example I have <

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