Switch Statement

Part of the Fundamentals section of Coddy's PHP journey — lesson 32 of 71.

When you need to compare a single variable against many specific values, the switch statement offers a cleaner alternative to long if-elseif chains.

The switch statement checks a variable once and then matches it against different case values:

<?php
$day = "Monday";

switch ($day) {
    case "Monday":
        echo "Start of the week";
        break;
    case "Friday":
        echo "Almost weekend";
        break;
    case "Saturday":
    case "Sunday":
        echo "Weekend!";
        break;
    default:
        echo "Regular day";
}
?>

PHP compares $day against each case. When it finds a match, it runs that block's code.

The break statement is crucial—it tells PHP to exit the switch after executing the matched case. Without it, PHP would continue running all the code below, even from other cases.

Notice how Saturday and Sunday share the same code by stacking cases together. The default case acts like an else—it runs when no other case matches.

<?php
$grade = "B";

switch ($grade) {
    case "A":
        echo "Excellent!";
        break;
    case "B":
        echo "Good job!";
        break;
    default:
        echo "Keep trying!";
}
?>

Use switch when comparing one variable against multiple exact values. For complex conditions or ranges, stick with if-elseif statements.

Challenge

Easy

Read a string command from input representing a traffic light color.

Use a switch statement to determine the appropriate action based on the color:

If the command is red, print Stop
If the command is yellow, print Slow down
If the command is green, print Go
If the command is flashing red or flashing yellow, print Proceed with caution
For any other value, print Invalid signal

Example:

If the input is green, the output should be:

Go

If the input is flashing red, the output should be:

Proceed with caution

If the input is blue, the output should be:

Invalid signal

Cheat sheet

The switch statement provides a cleaner way to compare a single variable against multiple specific values:

<?php
$day = "Monday";

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

The break statement exits the switch after executing the matched case. Without it, PHP continues running code from subsequent cases.

Multiple cases can share the same code by stacking them:

<?php
switch ($day) {
    case "Saturday":
    case "Sunday":
        echo "Weekend!";
        break;
}
?>

The default case runs when no other case matches, similar to an else statement.

Use switch statements for comparing one variable against multiple exact values. For complex conditions or ranges, use if-elseif statements instead.

Try it yourself

<?php
// Read input
$command = trim(fgets(STDIN));

// TODO: Write your code below using a switch statement
// Determine the appropriate action based on the traffic light color


?>

Test yourself

This lesson includes a short quiz. Start the lesson to answer it and track your progress.

All lessons in Fundamentals

2Variables and Data Types

Numbers Strings and Quotes Booleans Naming Conventions Recap - Variable Init Empty Variables String Concatenation Getting User Input Cast to Different Types

5Conditional Logic

If Statement If - Else The Ternary Operator Null Coalescing OperatorSwitch StatementRecap - Making Decisions

8Loops

For Loop While Loop Foreach Loop Looping with Keys and Values Break Statement Continue Statement Recap - Iterating Over Data

11Final Challenges

Challenge - Factorial Calc Challenge - Longest Word Challenge - Vowel Counter