PHP Operators

Operators are used to performing operations on some values.

PHP Operators can be categorized in following forms:

Arithmetic operators
Assignment operators
Comparison operators
Increment/Decrement operators
Logical operators
String operators
Array operators
Conditional or Ternary Operators

Arithmetic operators:

The arithmetic operators are used to perform common arithmetical operations, such as addition, subtraction, multiplication etc. Here's a complete list of PHP's arithmetic operators.

Operator	Description	Example	Explanation
`+`	Addition	`$x + $y`	Addition of two numbers
`-`	Subtraction	`$x - $y`	Subtraction of two numbers
`*`	Multiplication	`$x * $y`	Multiplication of two numbers
`/`	Division	`$x / $y`	Quotient of $x and $y
`%`	Modulus	`$x % $y`	Remainder of $x divided by $y

Example:

<?php
  $x = 16; // Variable 1
  $y = 5; // Variable 2
 
  // Some arithmetic operations on these two variables
  echo ($x + $y), "\n"; 
  echo($x - $y), "\n";
  echo($x * $y), "\n";
  echo($x / $y), "\n";
  echo($x % $y), "\n";
?>

Output : 

21
11
80
3.2
1

Assignment Operators:

The assignment operators are used to assign value to different variables. The basic assignment operator is "=".

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

Example :

<?php
  // Simple assign operator
  $y = 25;
  echo $y, "\n";
 
  // Add then assign operator
  $y = 25;
  $y += 75;
  echo $y, "\n";
 
  // Subtract then assign operator
  $y = 60;
  $y -= 10;
  echo $y, "\n";
 
  // Multiply then assign operator
  $y = 10;
  $y *= 5;
  echo $y, "\n";
 
  // Divide then assign(quotient) operator
  $y = 50;
  $y /= 5;
  echo $y, "\n";
 
  // Divide then assign(remainder) operator
  $y = 51;
  $y %= 5;
  echo $y;
?>

Output :
25
100
50
50
10
1

Comparison operators:

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

Operator	Name	Example	Explanation
==	Equal	$a == $b	Return TRUE if $a is equal to $b
===	Identical	$a === $b	Return TRUE if $a is equal to $b, and they are of same data type
!==	Not identical	$a !== $b	Return TRUE if $a is not equal to $b, and they are not of same data type
!=	Not equal	$a != $b	Return TRUE if $a is not equal to $b
<>	Not equal	$a <> $b	Return TRUE if $a is not equal to $b
<	Less than	$a < $b	Return TRUE if $a is less than $b
>	Greater than	$a > $b	Return TRUE if $a is greater than $b
<=	Less than or equal to	$a <= $b	Return TRUE if $a is less than or equal $b
>=	Greater than or equal to	$a >= $b	Return TRUE if $a is greater than or equal $b
<=>	Spaceship	$a <=>$b	Return -1 if $a is less than $b Return 0 if $a is equal $b Return 1 if $a is greater than $b

Example:

<?php
  $a = 100;
  $b = 50;
  $c = "100";
 
  // Here var_dump function has been used to
  // display structured information. We will learn
  // about this function in complete details in further
  // articles.
  var_dump($a == $c) + "\n";
  var_dump($a != $b) + "\n";
  var_dump($a <> $b) + "\n";
  var_dump($a === $c) + "\n";
  var_dump($a !== $c) + "\n";
  var_dump($a < $b) + "\n";
  var_dump($a > $b) + "\n";
  var_dump($a <= $b) + "\n";
  var_dump($a >= $b);
?>

Output: 
bool(true)
bool(true)
bool(true)
bool(false)
bool(true)
bool(false)
bool(true)
bool(false)
bool(true)

Increment / Decrement operators:

The increment/decrement operators are used to increment/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
$x = 5;
echo ++$x; // Outputs: 6
echo $x;   // Outputs: 6
 
$x = 5;
echo $x++; // Outputs: 5
echo $x;   // Outputs: 6
 
$x = 5;
echo --$x; // Outputs: 4
echo $x;   // Outputs: 4
 
$x = 5;
echo $x--; // Outputs: 5
echo $x;   // Outputs: 4
?>

Logical Operators:

The PHP logical operators are used to combine conditional statements.

Operator	Description	Example
and	Called Logical AND operator. If both the operands are true then condition becomes true.	(A and B) is true.
or	Called Logical OR Operator. If any of the two operands are non zero then condition becomes true.	(A or B) is true.
&&	Called Logical AND operator. If both the operands are non zero then condition becomes true.	(A && B) is true.
\|\|	Called Logical OR Operator. If any of the two operands are non zero then condition becomes true.	(A \|\| B) is true.
!	Called Logical NOT Operator. Use to reverses the logical state of its operand. If a condition is true then Logical NOT operator will make false.	!(A && B) is false.

String Operators:

The string operators are used to perform the operation on strings.

Operator	Name	Example	Explanation
.	Concatenation	$a . $b	Concatenate both $a and $b
.=	Concatenation and Assignment	$a .= $b	First concatenate $a and $b, then assign the concatenated string to $a, e.g. $a = $a . $b

Array Operators:

The array operators are used in case of array. Basically, these operators are used to compare the values of arrays.

Operator	Name	Example	Explanation
+	Union	$a + $y	Union of $a and $b
==	Equality	$a == $b	Return TRUE if $a and $b have same key/value pair
!=	Inequality	$a != $b	Return TRUE if $a is not equal to $b
===	Identity	$a === $b	Return TRUE if $a and $b have same key/value pair of same type in same order
!==	Non-Identity	$a !== $b	Return TRUE if $a is not identical to $b
<>	Inequality	$a <> $b	Return TRUE if $a is not equal to $b

Conditional or Ternary Operators:

The PHP Conditional or Ternary Operators are used to set a value depending on conditions:

Operator	Name	Example	Result
?:	Ternary	$x = expr1 ? expr2 : expr3	Returns the value of $x. The value of $x is expr2 if expr1 = TRUE. The value of $x is expr3 if expr1 = FALSE
??	Null coalescing	$x = expr1 ?? expr2	Returns the value of $x. The value of $x is expr1 if expr1 exists, and is not NULL. If expr1 does not exist, or is NULL, the value of $x is expr2. Introduced in PHP 7