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

?>

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 

?>

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! 

?>

PHP Increment / Decrement Operators
Operator Name Description
++$x Preincrement Increments $x by one, then returns $x
$x++ Postincrement Returns $x, then increments $x by one
–$x Predecrement Decrements $x by one, then returns $x
$x– Postdecrement 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 

?>

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); 

?>

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
!== Nonidentity $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); 

?>
