switch

When one variable has to be compared with several values, a chain of if and elseif gets long. The switch statement writes such a choice more compactly.

A simple switch

The value goes in parentheses, and each branch starts with the word case:

<?php
 
$day = 3;
 
switch ($day) {
    case 1:
        echo 'Monday';
        break;
    case 3:
        echo 'Wednesday';
        break;
}

PHP finds the branch with the matching value and runs its code.

The default branch

If no option matched, the default branch runs:

<?php
 
$color = 'purple';
 
switch ($color) {
    case 'red':
        echo 'Stop';
        break;
    case 'green':
        echo 'Go';
        break;
    default:
        echo 'Unknown signal';
}

Why break is needed

break ends the switch. Without it, execution "falls through" into the next branch:

<?php
 
$level = 1;
 
switch ($level) {
    case 1:
        echo 'one ';
    case 2:
        echo 'two ';
        break;
    case 3:
        echo 'three';
}

This prints "one two": the first branch has no break, so the second one ran too.

Several values, one branch

Fall-through is used on purpose to handle several values with the same code:

<?php
 
$day = 6;
 
switch ($day) {
    case 6:
    case 7:
        echo 'Weekend';
        break;
    default:
        echo 'Working day';
}

switch or match

The match expression from the lesson on conditions solves the same task and returns a value:

<?php
 
$day = 6;
 
$type = match ($day) {
    6, 7 => 'Weekend',
    default => 'Working day',
};
 
echo $type; // Weekend

When you need to pick a value, use match. When a branch has several actions, use switch.

Common mistake

switch compares loosely. The string '1' and the number 1 are equal to it, and the first matching branch wins:

<?php
 
$value = '1';
 
switch ($value) {
    case 1:
        echo 'the number one';
        break;
    case '1':
        echo 'the string one';
        break;
}

This prints "the number one". If the type matters, use match.