PHP Conditionals

last modified October 22, 2026

In this article, we explore PHP conditionals, which are control structures used to make decisions in code. Conditionals allow you to execute different blocks of code based on whether certain conditions are true or false.

Main Features of PHP Conditionals

• if: Executes a block of code if a condition is true.
• else: Executes a block of code if the if condition is false.
• elseif: Checks additional conditions if the previous if or elseif conditions are false.
• switch: Executes one of many blocks of code based on the value of a variable.
• ternary operator: A shorthand for simple if-else conditions.

Conditionals are essential for controlling the flow of your PHP programs.

Basic Usage of Conditionals

The following example demonstrates the basic usage of the if statement in PHP.

<?php

declare(strict_types=1);

$age = 20;

if ($age >= 18) {
    echo "You are an adult.\n";
}

In this program, the if statement checks if the $age variable is greater than or equal to 18. If true, it prints "You are an adult."

$ php main.php
You are an adult.

if-else Statement

The following example demonstrates the if-else statement.

<?php

declare(strict_types=1);

$age = 15;

if ($age >= 18) {
    echo "You are an adult.\n";
} else {
    echo "You are a minor.\n";
}

In this program, the else block is executed if the if condition is false.

$ php main.php
You are a minor.

elseif Statement

The following example demonstrates the elseif statement.

<?php

declare(strict_types=1);

$age = 25;

if ($age < 18) {
    echo "You are a minor.\n";
} elseif ($age < 30) {
    echo "You are a young adult.\n";
} else {
    echo "You are an adult.\n";
}

In this program, the elseif block is executed if the first if condition is false and the elseif condition is true.

$ php main.php
You are a young adult.

Ternary Operator

The following example demonstrates the ternary operator.

<?php

declare(strict_types=1);

$age = 20;

$message = ($age >= 18) ? "You are an adult.\n" : "You are a minor.\n";
echo $message;

In this program, the ternary operator is used as a shorthand for the if-else statement.

$ php main.php
You are an adult.

switch Statement

The following example demonstrates the switch statement.

<?php

declare(strict_types=1);

$day = "Monday";

switch ($day) {
    case "Monday":
        echo "Today is Monday.\n";
        break;
    case "Tuesday":
        echo "Today is Tuesday.\n";
        break;
    default:
        echo "Today is not Monday or Tuesday.\n";
}

In this program, the switch statement checks the value of $day and executes the corresponding block of code.

$ php main.php
Today is Monday.

Nested if Statements

The following example demonstrates nested if statements.

<?php

declare(strict_types=1);

$age = 25;
$isStudent = true;

if ($age >= 18) {
    if ($isStudent) {
        echo "You are an adult student.\n";
    } else {
        echo "You are an adult.\n";
    }
} else {
    echo "You are a minor.\n";
}

In this program, a nested if statement is used to check additional conditions.

$ php main.php
You are an adult student.

Logical Operators

The following example demonstrates the use of logical operators in conditionals.

<?php

declare(strict_types=1);

$age = 25;
$isStudent = true;

if ($age >= 18 && $isStudent) {
    echo "You are an adult student.\n";
} else {
    echo "You are not an adult student.\n";
}

In this program, the && (logical AND) operator is used to combine multiple conditions.

$ php main.php
You are an adult student.

Null Coalescing Operator

The following example demonstrates the null coalescing operator.

<?php

declare(strict_types=1);

$name = null;

$username = $name ?? "Guest";
echo "Welcome, $username!\n";

In this program, the null coalescing operator (??) is used to assign a default value if the variable is null.

$ php main.php
Welcome, Guest!

Combining Conditions

The following example demonstrates combining multiple conditions.

<?php

declare(strict_types=1);

$age = 25;
$isStudent = false;
$hasJob = true;

if (($age >= 18 && $hasJob) || $isStudent) {
    echo "You are eligible for the program.\n";
} else {
    echo "You are not eligible for the program.\n";
}

In this program, multiple conditions are combined using logical operators.

$ php main.php
You are eligible for the program.

match Expression

The match expression, available since PHP 8.0, is a compact alternative to switch. It compares values strictly, returns a value, and has no fall-through.

<?php

function describe(int $code): string
{
    return match (true) {
        $code >= 500 => "Server error",
        $code >= 400 => "Client error",
        $code >= 300 => "Redirection",
        $code >= 200 => "Success",
        default => "Informational",
    };
}

foreach ([200, 301, 404, 503, 100] as $code) {
    echo "$code: ", describe($code), "\n";
}

try {
    echo match (5) {
        1, 2 => "low",
        3, 4 => "medium",
    };
} catch (\UnhandledMatchError $e) {
    echo $e->getMessage(), "\n";
}

With match (true) each arm is a condition, and the first one that evaluates to true wins. Several values can share an arm, separated by commas. If no arm matches and there is no default, PHP throws an UnhandledMatchError, unlike switch, which silently does nothing.

$ php match.php
200: Success
301: Redirection
404: Client error
503: Server error
100: Informational
Unhandled match case of type int

Null coalescing assignment

The ??= operator assigns a value only if the variable is not set or is null.

<?php

$config = ['host' => 'localhost'];

$config['host'] ??= 'example.com';
$config['port'] ??= 8080;

print_r($config);

The host key already exists and is not null, so it keeps its value. The missing port key gets the default value. This replaces the longer isset check followed by an assignment.

$ php coalesce_assign.php
Array
(
    [host] => localhost
    [port] => 8080
)

Source

PHP Conditionals - Documentation

In this article, we have shown how to use conditionals in PHP for control flow. Conditionals are a powerful tool for making decisions in your code.

Author

My name is Jan Bodnar, and I am a passionate programmer with extensive programming experience. I have been writing programming articles since 2007. To date, I have authored over 1,400 articles and 8 e-books. I possess more than ten years of experience in teaching programming.

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