Using if…else Condition in PHP

Welcome back to our PHP tutorial series! In this article, we’ll explore how to use conditional statements in PHP, specifically focusing on the if...else construct. Conditional statements allow your code to make decisions and execute different blocks of code based on certain conditions. Let’s dive in!

Basic if Statement

The if statement executes a block of code if the specified condition is true.

Syntax

if (condition) {
    // code to be executed if condition is true
}

Example

<?php
$age = 20;

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

Output:

You are an adult.

if…else Statement

The if...else statement allows you to execute one block of code if the condition is true, and another block if the condition is false.

Syntax

if (condition) {
    // code to be executed if condition is true
} else {
    // code to be executed if condition is false
}

Example

<?php
$age = 16;

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

Output:

You are a minor.

if…elseif…else Statement

The if...elseif...else statement allows you to check multiple conditions and execute different blocks of code depending on which condition is true.

Syntax

if (condition1) {
    // code to be executed if condition1 is true
} elseif (condition2) {
    // code to be executed if condition2 is true
} else {
    // code to be executed if neither condition1 nor condition2 is true
}

Example

<?php
$score = 85;

if ($score >= 90) {
    echo "Grade: A";
} elseif ($score >= 80) {
    echo "Grade: B";
} elseif ($score >= 70) {
    echo "Grade: C";
} elseif ($score >= 60) {
    echo "Grade: D";
} else {
    echo "Grade: F";
}
?>

Output:

Grade: B

Nested if Statements

You can nest if statements within each other to create more complex conditional logic.

Example

<?php
$age = 20;
$has_permission = true;

if ($age >= 18) {
    if ($has_permission) {
        echo "You can enter the club.";
    } else {
        echo "You need permission to enter the club.";
    }
} else {
    echo "You are not allowed to enter the club.";
}
?>

Output:

You can enter the club.

Ternary Operator

The ternary operator is a shorthand for the if...else statement. It’s useful for simple conditions.

Syntax

condition ? true_value : false_value

Example

<?php
$age = 20;
$status = ($age >= 18) ? "adult" : "minor";
echo "You are an " . $status . ".";
?>

Output:

You are an adult.

Null Coalescing Operator

The null coalescing operator (??) is used to return the first operand if it exists and is not null; otherwise, it returns the second operand.

Syntax

$value = $var ?? default_value;

Example

<?php
$username = $_GET['username'] ?? 'Guest';
echo "Hello, " . $username . "!";
?>

Output:

If $_GET['username'] is not set, the output will be:

Hello, Guest!

Conclusion

Using conditional statements in PHP is crucial for controlling the flow of your program based on different conditions. You’ve learned how to use if, if...else, if...elseif...else, nested if statements, the ternary operator, and the null coalescing operator.

In our next article, we’ll explore PHP loops, which allow you to execute a block of code multiple times. Stay tuned and happy coding!

As always, if you have any questions or need further clarification, feel free to leave a comment below. We’re here to help you on your PHP journey!