'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

The IE or FF detector
Hello Friends,

Problem of today ( we seek for php help ) as following ,

we know all th

Need help: how to catch acess of undefined class properties
Hello. I am learning OO with PHP and have hit a problem.
Some code runs as perfectly valid code,

PHP File Upload Problem
Hi, I have written a very simple file upload script but it fails for reasons I can't explain. Hope

extract a file from zip file
hi,
i know how to unzip a zip file in php, but is there a way to just extract a certain file only

Multi-image upload problems
Lets see if I can get some help on this one. Can anyone show me what I am doing wrong here. I'm just

Placing and array within an array then sorting it!
I have a page that runs two large mysql queries and saves the results into arrays, in php I then per

Need help/w Page: 1,2,3,4 function!
So I have this code im working on where it's ment to display seperate pages having 20 logs each
I

replacements
I have a variable in my PHP script like

ASSFDDDDDDDDDDDDDASDDDDDDDDARYTRHKKHHHHHHHHHHH and p

SCO Unix
I know this might not be the place to ask, but, can anyone tell me if SCO Unix comes with PHP built

Problem with the Update command used with a sqldataadapter
I'm connected to a database on an SQL Server and I'm using a sqldataadapter, sqlconnection, sqldatas

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