'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

Add a sign-up feature to a flat file login script
I'm working on a flat file login script and I would like to add a sign-up feature to it with a email

Setting a default timezone?
I have read about how to change the timezone in PHPMYADMIN, but it changes back, it doesn't STAY the

admin with my register system?
Hey i wana make it so i can make a admin level on my register system , I'm kinda new to php to im no

error with opendir
when i do this

if ($handle = opendir($dir)) {
while (false !== ($file = readdir($han

how can i make a .gif images for my site
Dear Friends ,

Pls solve my problem , I am starting making new site but i dont know how can i

PHP switch function help
Hi, I am trying to create a search function for a directory website. On the search function on html

foreach and array need help combining
Hi guys.

Here's the code

Code: array(
'tag' => 'code',<

Preg_match question
I want to use preg_match to make sure a string is always 6 characters long and only contains 0-9 and

Error In Syntax
I got this error:

Code: Parse error: syntax error, unexpected '>' in /home/bucket/publ

What makes a script your own?
If someone finds a login script online, and changes some variable names around and some other minor

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