Integers

Syntax

Integers can be specified in decimal (10-based), hexadecimal (16-based) or octal (8-based) notation, optionally preceded by a sign (- or +).

If you use the octal notation, you must precede the number with a 0 (zero), to use hexadecimal notation precede the number with 0x.

Example 6-1. Integer literals $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)

The size of an integer is platform-dependent, although a maximum value of about two billion is the usual value (that's 32 bits signed).

Integer overflow

If you specify a number beyond the bounds of the integer-type, it will be interpreted as a double instead.

$large_number =  2147483647;
var_dump($large_number);
// output: int(2147483647)
$large_number =  2147483648;
var_dump($large_number);
// output: float(2147483648) 
       

$million = 1000000;
$large_number =  50000 * $million;
var_dump($large_number);
// output: float(50000000000)
       

Converting to integer

To explicitly convert a value to integer, use either the (int) or the (integer) cast. However, in most cases you do not need to use the cast, since a value will be autmatically converted if an operator, function or control structure requires a integer-argument.

See also type-juggling.

echo (int) ( (0.1+0.7) * 10 ); // echoes 7!