'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

rdns with php
I am trying to build a script that will show all of the different domains that are hosted on the sam

Allegro crashes when running load_bitmap. Why?
I can not get Allegro to load any BMP images. Here is a section of test code. The picture is in the

2 decima places & How to reload my page
Hello There,

How do i put full-stop (.) after second figure from behind? ie if i have 123456

Consuming MII WebService in Java WebDynpro
Hello,

We are facing a strange situation...

We define a transaction in MII to

registration form
first time posting. did some searches but didnt find exactly what i am looking for. dont flame cause

Problem in String replace program's output
Hi all,
I was trying to make a program which accepts a string and replaces it with another stri

media recovery
Hi,
i startup the database i got the error

SQL> startup
ORACLE instance started.

Loop Through Date Range
Hi guys,
I have date range as parameter like 01/JAN/2009 TO 16/JAN/2009 now i want to loop thro

building a function with multiple outputs
I want to build a function that has multiple outputs.

I know but am not to sure how I should

Parse Error
Hi Guys,

I have a function in my class which returns a string link variable. The problem is i

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