PHP 5 Operators

This chapter shows the different operators that can be used in PHP scripts.

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PHP Arithmetic Operators

Operator	Name	Example	Result
+	Addition	$x + $y	Sum of $x and $y
-	Subtraction	$x - $y	Difference of $x and $y
*	Multiplication	$x * $y	Product of $x and $y
/	Division	$x / $y	Quotient of $x and $y
%	Modulus	$x % $y	Remainder of $x divided by $y
**	Exponentiation	$x ** $y	Result of raising $x to the $y'th power (Introduced in PHP 5.6)

The example below shows the different results of using the different arithmetic operators:

Example

<?php
$x=10;
$y=6;
echo ($x + $y); // outputs 16
echo ($x - $y); // outputs 4
echo ($x * $y); // outputs 60
echo ($x / $y); // outputs 1.6666666666667
echo ($x % $y); // outputs 4
?>

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PHP Assignment Operators

The PHP assignment operators are used to write a value to a variable.
The basic assignment operator in PHP is "=". It means that the left operand gets set to the value of the assignment expression on the right.

Assignment	Same as...	Description
x = y	x = y	The left operand gets set to the value of the expression on the right
x += y	x = x + y	Addition
x -= y	x = x - y	Subtraction
x *= y	x = x * y	Multiplication
x /= y	x = x / y	Division
x %= y	x = x % y	Modulus

The example below shows the different results of using the different assignment operators:

Example

<?php
$x=10;
echo $x; // outputs 10

$y=20;
$y += 100;
echo $y; // outputs 120

$z=50;
$z -= 25;
echo $z; // outputs 25

$i=5;
$i *= 6;
echo $i; // outputs 30

$j=10;
$j /= 5;
echo $j; // outputs 2

$k=15;
$k %= 4;
echo $k; // outputs 3
?>

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PHP String Operators

Operator	Name	Example	Result
.	Concatenation	$txt1 = "Hello" $txt2 = $txt1 . " world!"	Now $txt2 contains "Hello world!"
.=	Concatenation assignment	$txt1 = "Hello" $txt1 .= " world!"	Now $txt1 contains "Hello world!"

The example below shows the results of using the string operators:

Example

<?php
$a = "Hello";
$b = $a . " world!";
echo $b; // outputs Hello world!

$x="Hello";
$x .= " world!";
echo $x; // outputs Hello world!
?>

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PHP Increment / Decrement Operators

Operator	Name	Description
++$x	Pre-increment	Increments $x by one, then returns $x
$x++	Post-increment	Returns $x, then increments $x by one
--$x	Pre-decrement	Decrements $x by one, then returns $x
$x--	Post-decrement	Returns $x, then decrements $x by one

The example below shows the different results of using the different increment/decrement operators:

Example

<?php
$x=10;
echo ++$x; // outputs 11

$y=10;
echo $y++; // outputs 10

$z=5;
echo --$z; // outputs 4

$i=5;
echo $i--; // outputs 5
?>

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PHP Comparison Operators

The PHP comparison operators are used to compare two values (number or string):

Operator	Name	Example	Result
==	Equal	$x == $y	True if $x is equal to $y
===	Identical	$x === $y	True if $x is equal to $y, and they are of the same type
!=	Not equal	$x != $y	True if $x is not equal to $y
<>	Not equal	$x <> $y	True if $x is not equal to $y
!==	Not identical	$x !== $y	True if $x is not equal to $y, or they are not of the same type
>	Greater than	$x > $y	True if $x is greater than $y
<	Less than	$x < $y	True if $x is less than $y
>=	Greater than or equal to	$x >= $y	True if $x is greater than or equal to $y
<=	Less than or equal to	$x <= $y	True if $x is less than or equal to $y

The example below shows the different results of using some of the comparison operators:

Example

<?php
$x=100;
$y="100";

var_dump($x == $y);
echo "<br>";
var_dump($x === $y);
echo "<br>";
var_dump($x != $y);
echo "<br>";
var_dump($x !== $y);
echo "<br>";

$a=50;
$b=90;

var_dump($a > $b);
echo "<br>";
var_dump($a < $b);
?>

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PHP Logical Operators

Operator	Name	Example	Result
and	And	$x and $y	True if both $x and $y are true
or	Or	$x or $y	True if either $x or $y is true
xor	Xor	$x xor $y	True if either $x or $y is true, but not both
&&	And	$x && $y	True if both $x and $y are true
||	Or	$x || $y	True if either $x or $y is true
!	Not	!$x	True if $x is not true

---

PHP Array Operators

The PHP array operators are used to compare arrays:

Operator	Name	Example	Result
+	Union	$x + $y	Union of $x and $y (but duplicate keys are not overwritten)
==	Equality	$x == $y	True if $x and $y have the same key/value pairs
===	Identity	$x === $y	True if $x and $y have the same key/value pairs in the same order and of the same types
!=	Inequality	$x != $y	True if $x is not equal to $y
<>	Inequality	$x <> $y	True if $x is not equal to $y
!==	Non-identity	$x !== $y	True if $x is not identical to $y

The example below shows the different results of using the different array operators:

Example

<?php
$x = array("a" => "red", "b" => "green");
$y = array("c" => "blue", "d" => "yellow");
$z = $x + $y; // union of $x and $y
var_dump($z);
var_dump($x == $y);
var_dump($x === $y);
var_dump($x != $y);
var_dump($x <> $y);
var_dump($x !== $y);
?>