Conditionals

if / else if / else

The if statement executes code when a condition is true:

ZYMBA

$score = 85;

if ($score >= 90) {
    $grade = "A";
} else if ($score >= 80) {
    $grade = "B";
} else if ($score >= 70) {
    $grade = "C";
} else {
    $grade = "F";
}

echo $grade; // "B"

Conditions can use any expression that evaluates to a truthy or falsy value:

ZYMBA

$name = "Alice";

if ($name) {
    echo "Name is set";
}

if (count $items > 0) {
    echo "Items available";
}

unless

The unless keyword is the inverse of if — it executes when the condition is false:

ZYMBA

$loggedIn = false;

unless ($loggedIn) {
    echo "Please log in";
}

This is equivalent to if (!$loggedIn) but reads more naturally for guard clauses:

ZYMBA

function $processOrder($order) {
    unless ($order is object) {
        throw new @Exception("Invalid order");
    }
    unless (exists $order.items) {
        throw new @Exception("Order has no items");
    }
    // Process...
}

Ternary operator

For simple conditional expressions:

ZYMBA

$status = ($score >= 60) ? "Pass" : "Fail";
$label  = ($count == 1)  ? "item" : "items";

echo "$count $label"; // "5 items"

Switch statement

The switch statement matches a value against multiple cases:

ZYMBA

$status = "shipped";

switch ($status) {
    case "pending":
        echo "Order is pending";
        break;
    case "shipped":
        echo "Order has been shipped";
        break;
    case "delivered":
        echo "Order delivered";
        break;
    default:
        echo "Unknown status";
}

Multiple values per case

A single case can match multiple values:

ZYMBA

$day = "Saturday";

switch ($day) {
    case "Monday", "Tuesday", "Wednesday", "Thursday", "Friday":
        echo "Weekday";
        break;
    case "Saturday", "Sunday":
        echo "Weekend";
        break;
}

Fall-through behavior

Without break, execution falls through to the next case:

ZYMBA

$level = 1;

switch ($level) {
    case 1:
        echo "one ";
    case 2:
        echo "two ";
        break;
    case 3:
        echo "three ";
}
// Output: one two (falls through from case 1 to case 2)

warning

Always include break in each case unless you intentionally want fall-through behavior.