Operators list

Arithmetic Operators

Example	Name	Result
–$a	Negation	Opposite of $a.
$a + $b	Addition	Sum of $a and $b.
$a – $b	Subtraction	Difference of $a and $b.
$a * $b	Multiplication	Product of $a and $b.
$a / $b	Division	Quotient of $a and $b.
$a % $b	Modulus	Remainder of $a divided by $b.

Assignment Operators

<?php $a = 5; ?>

<?php $a = ($b = 2) + 5;  // $a = 7 ?>

<?php
  $a = 2;
  $a += 3; // sets $a to 5, equivalent to: $a = $a + 5;
  $b = "Hello ";
  $b .= "World!"; // sets $b to "Hello There!", equivalent to  $b = $b . "There!";  ( dot is for contatenation)
?>

 Assignment by Reference

<?php
  $a = 3;
  $b = &$a; // $b is a reference to $a - changes of $a will apply to $b too
  echo $a . $b;   // prints 33

  $a = 4;
  echo $a . $b;   // prints 44

  class C {}

  $o = &new C;  // as of PHP 5 classes are passed by default by reference
              // as of PHP 5.3 this will throw an E_DEPRECATED error
?>

 Bitwise Operators

Format	Name	Example
$a & $b	And	1001 & 0101  = 0001
$a | $b	Or (inclusive or)	1001 | 0101 = 1101
$a ^ $b	Xor (exclusive or)	1001 ^ 0101  = 0100
~ $a	Not	~ 1001 = 0110
$a << $b	Shift left	0010 << 1 = 0100
$a >> $b	Shift right	Shift the bits of $a $b steps to the right (each step means “divide by two”)