Operators in PHP are symbols that instruct the PHP processor to carry out specific actions. For instance, the addition (+) operator directs PHP to add two variables or values together. Similarly, the greater-than (>) operator instructs PHP to compare two values.
Below are explanations of various operators utilized in PHP.
Arithmetic operators in PHP are essential for performing basic mathematical operations like addition, subtraction, multiplication, and more. Here is a comprehensive list of PHP's arithmetic operators:
| Operator | Description | 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 |
Here's an example that demonstrates how these arithmetic operators are used:
<?php
$x = 10;
$y = 4;
echo($x + $y); // 0utputs: 14
echo($x - $y); // 0utputs: 6
echo($x * $y); // 0utputs: 40
echo($x / $y); // 0utputs: 2.5
echo($x % $y); // 0utputs: 2
?>Assignment operators are essential in PHP for assigning values to variables.
| Operator | Description | Example | Is The Same As |
|---|---|---|---|
= |
Assign | $x = $y |
$x = $y |
+= |
Add and assign | $x += $y |
$x = $x + $y |
-= |
Subtract and assign | $x -= $y |
$x = $x - $y |
*= |
Multiply and assign | $x *= $y |
$x = $x * $y |
/= |
Divide and assign quotient | $x /= $y |
$x = $x / $y |
%= |
Divide and assign modulus | $x %= $y |
$x = $x % $y |
Here's an example that illustrates how these assignment operators work:
<?php
$x = 10;
echo $x; // Outputs: 10
$x = 20;
$x += 30;
echo $x; // Outputs: 50
$x = 50;
$x -= 20;
echo $x; // Outputs: 30
$x = 5;
$x *= 25;
echo $x; // Outputs: 125
$x = 50;
$x /= 10;
echo $x; // Outputs: 5
$x = 100;
$x %= 15;
echo $x; // Outputs: 10
?>Comparison operators in PHP are utilized to evaluate and compare two values in a Boolean context.
| 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 |
< |
Less than | $x < $y |
True if $x is less than $y |
> |
Greater than | $x > $y |
True if $x is greater 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 |
Here's an example that demonstrates how these comparison operators are used:
<?php
$x = 25;
$y = 35;
$z = "25";
var_dump($x == $z); // Outputs: boolean true
var_dump($x === $z); // Outputs: boolean false
var_dump($x != $y); // Outputs: boolean true
var_dump($x !== $z); // Outputs: boolean true
var_dump($x < $y); // Outputs: boolean true
var_dump($x > $y); // Outputs: boolean false
var_dump($x <= $y); // Outputs: boolean true
var_dump($x >= $y); // Outputs: boolean false
?>Increment and decrement operators in PHP are employed to increase or decrease the value of a variable.
| Operator | Name | Effect |
|---|---|---|
++$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 |
Here's an example that demonstrates how these increment and decrement operators are used:
<?php
$x = 10;
echo ++$x; // Outputs: 11
echo $x; // Outputs: 11
$x = 10;
echo $x++; // Outputs: 10
echo $x; // Outputs: 11
$x = 10;
echo --$x; // Outputs: 9
echo $x; // Outputs: 9
$x = 10;
echo $x--; // Outputs: 10
echo $x; // Outputs: 9
?>Logical operators in PHP are used to combine conditional statements.
| 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 |
Here's an example that demonstrates how these logical operators are used:
<?php
$year = 2014;
// Leap years are divisible by 400 or by 4 but not 100
if(($year % 400 == 0) || (($year % 100 != 0) && ($year % 4 == 0))){
echo "$year is a leap year.";
} else{
echo "$year is not a leap year.";
}
?>PHP includes specific operators designed for working with strings.
| Operator | Description | Example | Result |
|---|---|---|---|
. |
Concatenation | $str1 . $str2 |
Concatenation of $str1 and $str2 |
.= |
Concatenation assignment | $str1 .= $str2 |
Appends the $str2 to the $str1 |
Here's an example that demonstrates how these string operators are used:
<?php
$x = "Hello";
$y = " World!";
echo $x . $y; // Outputs: Hello World!
$x .= $y;
echo $x; // Outputs: Hello World!
?>PHP provides operators specifically for comparing arrays.
| Operator | Name | Example | Result |
|---|---|---|---|
+ |
Union | $x + $y |
Union of $x and $y |
== |
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 |
Here's an example that demonstrates how these arithmetic operators are used:
<?php
$x = array("a" => "Red", "b" => "Green", "c" => "Blue");
$y = array("u" => "Yellow", "v" => "Orange", "w" => "Pink");
$z = $x + $y; // Union of $x and $y
var_dump($z);
var_dump($x == $y); // Outputs: boolean false
var_dump($x === $y); // Outputs: boolean false
var_dump($x != $y); // Outputs: boolean true
var_dump($x <> $y); // Outputs: boolean true
var_dump($x !== $y); // Outputs: boolean true
?>Introduced in PHP 7, the spaceship operator (<=>) allows you to compare two expressions, also known as the combined comparison operator.
When used, the spaceship operator returns 0 if both operands are equal, 1 if the left operand is greater, and -1 if the right operand is greater. It effectively provides a three-way comparison, summarized in the following table:
| Operator | <=> Equivalent |
|---|---|
$x < $y |
($x <=> $y) === -1 |
$x <= $y |
($x <=> $y) === -1 || ($x <=> $y) === 0 |
$x == $y |
($x <=> $y) === 0 |
$x != $y |
($x <=> $y) !== 0 |
$x >= $y |
($x <=> $y) === 1 || ($x <=> $y) === 0 |
$x > $y |
($x <=> $y) === 1 |
Here's an example that demonstrates how these spaceship operators are used:
<?php
// Comparing Integers
echo 1 <=> 1; // Outputs: 0
echo 1 <=> 2; // Outputs: -1
echo 2 <=> 1; // Outputs: 1
// Comparing Floats
echo 1.5 <=> 1.5; // Outputs: 0
echo 1.5 <=> 2.5; // Outputs: -1
echo 2.5 <=> 1.5; // Outputs: 1
// Comparing Strings
echo "x" <=> "x"; // Outputs: 0
echo "x" <=> "y"; // Outputs: -1
echo "y" <=> "x"; // Outputs: 1
?>