PHP Conditional Statements

Conditional statements are used to perform different actions for different decisions. They allow your script to make choices, which is the core of dynamic programming.

1. The if Statement

The if statement executes a block of code only if a specified condition is TRUE.

Example:

PHP

<?php
    $t = date("H"); // Gets the current hour (0 to 23)

    if ($t < "20") {
        echo "Have a good day!";
    }
?>

2. The if...else Statement

The if...else statement executes one block of code if the condition is TRUE, and a different block of code if the condition is FALSE.

Example:

PHP

<?php
    $age = 17;

    if ($age >= 18) {
        echo "You are eligible to vote.";
    } else {
        echo "You are too young to vote.";
    }
?>

3. The if...elseif...else Statement

This statement specifies a new condition to test if the first condition is FALSE. You can use any number of elseif blocks.

Example:

PHP

<?php
    $score = 85;

    if ($score >= 90) {
        echo "Grade: A";
    } elseif ($score >= 80) {
        echo "Grade: B"; // This code will execute
    } else {
        echo "Grade: C or lower";
    }
?>

4. The switch Statement

The switch statement is used to perform different actions based on different conditions, but for a single variable being compared against multiple possible values. It’s often cleaner than a long if...elseif...else chain.

Example:

PHP

<?php
    $day = "Monday";

    switch ($day) {
        case "Monday":
            echo "Start of the week!";
            break;
        case "Friday":
            echo "Almost the weekend!";
            break;
        default:
            echo "Just a regular day.";
    }
?>