'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 Code reffering to database, doing something wrong.. pls help
Well i am quite new with PHP
and for school we have to make a PHP script which reffers to a Data

IS Retail & Manufacturing
Hi

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

problems with search form numerical "between" sending by php
I am trying to display the results of a search, on a sql database, on a web page. I set up html &quo

How do I send data using an html link
Hi

If I have
<a href="main_file.php">

How do I send data t

WHYISNT THIS MYSQL STATEMNT NOT WORKING? (php)
caps because its absolutely rediculous.
i dontunderstand why its not working. there is a column c

multipart emiail forms
Hi All,

I am new to the boards and I've been working on a form (which is rather massive, imo

How do I use a global footer..?
If my index.php has a bole bunch of if functions and exit's in them

Rounding a number queried from a database
I know that to display a rounded number you just do echo "round($number)";. But how would

do while...woes
I'm sure this is childsplay but it is stumping me, everytime i try what I think would make this work

Javascript using window.location seems to lose state
Not sure what forum so let me know if I'm in the wrong place. I have a main window with a ajax grid

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