integer

integer — Is a number of the set ℤ = {..., -2, -1, 0, 1, 2, ...}.

Can be specified in decimal (base 10), hexadecimal (base 16), octal (base 8) or binary (base 2) notation.

<?php
$a = 1234; // decimal number
$a = -123; // a negative number
$a = 0123; // octal number (equivalent to 83 decimal)
$a = 0x1A; // hexadecimal number (equivalent to 26 decimal)
$a = 0b11111111; // binary number (equivalent to 255 decimal)
?>

<?php
$large_number = 2147483647;
var_dump($large_number);                     // int(2147483647)

$large_number = 2147483648;
var_dump($large_number);                     // float(2147483648)

$million = 1000000;
$large_number =  50000 * $million;
var_dump($large_number);                     // float(50000000000)
?>

<?php
$large_number = 9223372036854775807;
var_dump($large_number);                     // int(9223372036854775807)

$large_number = 9223372036854775808;
var_dump($large_number);                     // float(9.2233720368548E+18)

$million = 1000000;
$large_number =  50000000000000 * $million;
var_dump($large_number);                     // float(5.0E+19)
?>

If PHP encounters a number beyond the bounds of the integer type, it will be interpreted as a float instead.

An operation which results in a number beyond the bounds of the integer type will return a float instead.

To explicitly convert a value to integer, use either the (int) or (integer) casts.
In most cases the cast is not needed, since a value will be automatically converted if an operator, function or control structure requires an integer argument.
A value can also be converted to integer with the intval() function.
If a resource is converted to an integer, then the result will be the unique resource number assigned to the resource by PHP at runtime.
FALSE will yield 0 (zero), and TRUE will yield 1 (one).
When converting from float to integer, the number will be rounded towards zero.
NULL is always converted to zero (0).
The behaviour of converting to integer is undefined for other types. Do not rely on any observed behaviour, as it can change without notice.

Integer literals

Integer overflow

Converting to integer

Related concepts

integer — Structure map

integer — Related pages:

Integers

Expressions

Arrays

Introduction

Strings

Type Operators