Developer Newsletter

PHP Manual
Prev	Chapter 15. Operators	Next

Bitwise Operators

Bitwise operators allow you to turn specific bits within an integer on or off. If both the left- and right-hand parameters are strings, the bitwise operator will operate on the characters' ASCII values.


<?php
echo 12 ^ 9; // Outputs '5'

echo "12" ^ "9"; // Outputs the Backspace character (ascii 8)
                 // ('1' (ascii 49)) ^ ('9' (ascii 57)) = #8

echo "hallo" ^ "hello"; // Outputs the ascii values #0 #4 #0 #0 #0
                        // 'a' ^ 'e' = #4
?>

Table 15-3. Bitwise Operators

Example	Name	Result
$a & $b	And	Bits that are set in both $a and $b are set.
$a \| $b	Or	Bits that are set in either $a or $b are set.
$a ^ $b	Xor	Bits that are set in $a or $b but not both are set.
~ $a	Not	Bits that are set in $a are not set, and vice versa.
$a << $b	Shift left	Shift the bits of $a $b steps to the left (each step means "multiply by two")
$a >> $b	Shift right	Shift the bits of $a $b steps to the right (each step means "divide by two")

Warning

Don't right shift for more than 32 bits on 32 bits systems. Don't left shift in case it results to number longer than 32 bits.

Prev	Home	Next
Assignment Operators	Up	Comparison Operators