Comparison Operators

Comparison operators allow you to compare two values.

These operators test two values against each other, and if they relate correctly, the test returns true.

If the relationship specified by the test is incorrect, the return value is false. All comparison operators take two values for input.

See the following table:

**Comparison Operators**
Operator Name	Example	Task
Equal `==`	$a == $b	Return `true` if `$a` and `$b` are equal, if not equal then return `false`
Identical `===`	$a === $b	Return `true` if `$a` and `$b` are equal and the same type, else return `false`
Not equal `!=`	$a != $b	Return `true` if `$a` and `$b` are not equal, if equal then return `false`
Not equal `<>`	$a <> $b	Return `true` if `$a` and `$b` are not equal, if equal then return `false`
Not identical `!==`	$a !== $b	Return `true` if `$a` and `$b` are unequal or different type, else return `false`
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 to `$b`
Greater than or equal to `>=`	$a >= $b	Return `true` if `$a` is greater than or `$b`

In above table, comparison operators determine whether the following conditions are present between two values:

Examples

Example 1: Comparing with equal operator ==

<?php
    $a = 'php';
    $b = 'php';
    var_dump($a == $b); //prints: bool(true)
?>

The above example displays the true result as $a and $b are equal in values

Example 2: Comparing with identical operator ===

<?php
    $a = 'php';
    $b = 'php';
    var_dump($a === $b); //prints: bool(true)
?>

The above example displays the true result as $a and $b are equal in values and also own the same type (string)

<?php
    $a = 1; //php integer
    $b = '1'; //php string
    var_dump($a === $b); //prints: bool(false)
?>

The above example displays the false result because data type of $a is string and data type of $b is integer and we know identtical operator === checks types and values of given inputs

Example 4: Comparing with not equal operators != and <>

<?php
    $a = 'php';
    $b = 'php';
    var_dump($a != $b); //prints: bool(false)
    
    $a = 'php';
    $b = 'php';
    var_dump($a <> $b); //prints: bool(false)
?>

The above example displays the false result because $a and $b are equal in values

Example 5: Comparing with not identical operator !==

<?php
    $a = 'php';
    $b = 'php';
    var_dump($a !== $b); //prints: bool(false)
    
    $c = 1;
    $d = '1';
    var_dump($c !== $d); //prints: bool(true)
    
?>

In above example the first part returns false result because $a and $b are equal in values and types, and second part returns true because $c and $d are not equal in types.

Example 6: Comparing with less than < and greater than >

<?php
    $a = 'a';
    $b = 'b';
    var_dump($a < $b); //prints: bool(true)
    var_dump($b > $a); //prints: bool(true)
    
    $c = 1;
    $d = 2;
    var_dump($c < $d); //prints: bool(true)
    var_dump($d > $c); //prints: bool(true)
?>

Less than < and greater than > do not compare the length of given values or variables, actually these operators compare the sequence, in numerical values 1 is smaller than 2, 2 is smaller than 3... and alphabetically a is smaller than b. See the abobe example, it outputs the same.

Example 6: Comparing with less than or equal to <= and greater than or equal to >=

<?php
    $a = 'a';
    $b = 'bzd';
    var_dump($a <= $b); //prints: bool(true)
    var_dump($b >= $a); //prints: bool(true)
    
    $a = 'a';
    $b = 'a';
    var_dump($a <= $b); //prints: bool(true)
    var_dump($b >= $a); //prints: bool(true)
    
    $c = 1;
    $d = 200;
    var_dump($c <= $d); //prints: bool(true)
    var_dump($d >= $c); //prints: bool(true)
?>

As we can see in above example, comapring 'a' <= 'b' and 'a' <= 'a' always return true.

Note: var_dump() function displays structured information i.e. type and value.

Comparison Operators

Examples

Contents and Related Tutorials