Operators in PHP

Operators in PHP are used to perform different operations on operands. Operators can be categorized in following types :

• Arithmetic operators
• Assignment operators
• Comparison operators
• Increment/Decrement operators
• Logical operators
• String operators
• Array operators

Arithmetic operators : Arithmetic operators are used with numeric values to perform common arithmetical operations, such as addition, subtraction, multiplication etc. Assume variable $x holds 20 and variable $y holds 10, then :

Operators	Name	Description	Example
+	Addition	Sum of $x and $y	$x + $y =30
-	Subtraction	Difference of $x and $y	$x - $y = -10
*	Multiplication	Products of $x and $y	$x * $y = 200
/	Division	Quotient of $x and $y	$x / $y = 2
%	Modulus	Remiander of $x divided by $y	$x % $y = 0
**	Exponentiation	Result of raising $x to the $y'th power	$x ** $y = 10240000000000

Example :

<?php
$a = 12;
$b = 8;
$c = $a + $b;
echo $c;
?>

Output :

20

Assignment operators : Assignment operators are used with numeric values to write a value to a variable.

Shorthand	Expression	Description
$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

Example :

<?php
$x = 10;
$y = 5;

$x += $y;
echo $x."<br>";
$x -= $y;
echo $x."<br>";
$x *= $y;
echo $x."<br>";
$x /= $y;
echo $x."<br>";
$x %= $y;
echo $x;
?>

Output :

15
10
50
10
0

Comparison operators : Comparison operators are used in PHP to compare two values (number or string).  Assume variable $x holds 20 and variable $y holds 10, then :

Operators	Name	Description	Example
==	Equal	Returns true if $x is equal to $y	($x == $y) is false
===	Identical	Returns true if $x is equal to $y, and they are of the same type	($x === $y) is false
!=	Not equal	Returns true if $x is not equal to $y	($x != $y) is true
<>	Not equal	Returns true if $x is not equal to $y	($x <> $y) is true
!==	Not identical	Returns true if $x is not equal to $y, or they are not of the same type	($x !== $y) is true
>	Greater than	Returns true if $x is greater than $y	($x > $y) is true
<	Less than	Returns true if $x is less than $y	($x < $y) is false
>=	Greater than or equal to	Returns true if $x is greater than or equal to $y	($x >= $y) is true
<=	Less than or equal to	Returns true if $x is less than or equal to $y	($x < $y) is false

Increment/Decrement operators : In PHP increment operators are used to increment a variable's value and decrement operators are used to decrement a variable's value.

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

Example :

<?php
$x = 10;
echo ++$x."<br>";
$y = 20;
echo $y++."<br>";
$a = 15;
echo --$a."<br>";
$b = 25;
echo $b--;
?>

Output :

11
20
14
25

Logical operators : Logical operators are used to combine conditional statements.

Operators	Name	Expression	Description
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

Example :

<?php
$x = 10;
$y=20;

if($x==10 and $y==20)
{
    echo "True"."<br>";
}

if($x==10 or $y==30)
{
    echo "True"."<br>";
}

if($x==10 and $y==20)
{
    echo "False"."<br>";
}

if($x !==20)
{
    echo "True"."<br>";
}
?>

Output :

True
True
False
True

String operators :

Operator	Name	Expression	Description
.	Concatenation	$txt_1 . $txt_2	Concatenation of $txt1 and $txt2
.=	Concatenation assignment	$txt_1 .= $txt_2	Appends $txt_2 to $txt_1

Example :

<?php
$txt_1 = "Hello";
$txt_2 = " world";
echo $txt_1 . $txt_2."<br>";

$txt_3 = "My";
$txt_4= " PHP";
$txt_3 .= $txt_4;
echo $txt_3;
?>

Output :

Hello world
My PHP

Array operators : Array operators are used in PHP to compare arrays.

Operator	Name	Expression	Description
+	Union	$x + $y	Union of $x and $y
==	Equality	$x == $y	Returns true if $x and $y have the same key/value pairs
===	Identity	$x === $y	Returns true if $x and $y have the same key/value pairs in the same order and of the same types
!=	Inequality	$x != $y	Returns true if $x is not equal to $y
<>	Inequality	$x <> $y	Returns true if $x is not equal to $y
!==	Non-identity	$x !== $y	Returns true if $x is not identical to $y

Example :

<?php
$x = array("a" => "red", "b" => "green"); 
$y = array("c" => "blue", "d" => "yellow"); 
print_r($x + $y);
?>

Output :

Array ( [a] => red [b] => green [c] => blue [d] => yellow )

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