Comparison Operators in PHP: A Comprehensive Guide

In PHP, comparison operators are used to compare two values and determine their relationship or equality. These operators evaluate expressions and return a Boolean result, either true or false, based on the comparison's outcome.

Here are the comparison operators available in PHP:

Equal (==): It checks if two values are equal, disregarding their data types. For example:

<?php
    $a=45;
    $b="45";
    var_dump($a==$b);
?>

Identical (===): It checks if two values are equal and have the same data type. For example:

<?php
    $a=45;
    $b=45;
    var_dump($a===$b);
?>

Not equal (!= or <>): It checks if two values are not equal, irrespective of their data types. For example:

<?php
   $a=45;
   $b=35;
   var_dump($a!=$b);
   var_dump($a<>$b);
?>

Not identical (!==): It checks if two values are not equal or do not have the same data type. For example:

<?php
   $a=45;
   $b="45";
   var_dump($a!==$b);
?>

Greater than (>): It checks if the left operand is greater than the right operand. For example:

<?php
    $age=25;
    var_dump($age>18);
?>

Less than (<) : It checks if the left operand is less than the right operand. For example:

<?php
    $a=45;
    $b=45;
    var_dump($a<$b);
?>

Greater than or equal to (>=): It checks if the left operand is greater than or equal to the right operand. For example:

<?php
    $age=25;
    var_dump($age>18);
    //Greater than or equal to    
    var_dump($age>=18);
?>

Less than or equal to(<=) : It checks if the left operand is less than or equal to the right operand. For example:

<?php
    $a=45;
    $b=45;
    var_dump($a<$b);
    //Less than or equal to    
    var_dump($a<=$b);
?>

spaceship operator

The spaceship operator, also known as the combined comparison operator, is a unique operator introduced in PHP 7. It is represented by the symbol <=>. The spaceship operator is used to compare two expressions and returns an integer value based on the comparison result.

Here's how the spaceship operator works:

If the left-hand side (LHS) expression is less than the right-hand side (RHS) expression, it returns -1.0
If the LHS expression is greater than the RHS expression, it returns 1.
If both expressions are equal, it returns 0.

Here's an example to demonstrate the usage of the spaceship operator:

<?php
    $a=250;
    $b=25;
    var_dump($a<=>$b);
?>

These comparison operators are commonly used in conditionals, such as if statements, to control the flow of program execution based on the evaluation of the expressions.

Comparison Operators in PHP: A Comprehensive Guide

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