PHP If...Else...Elseif

PHP If, Else, and Elseif: Writing Clear Conditional Logic

Conditional statements let your PHP application make decisions based on user roles, input values, or database states. PHP evaluates each condition inside if (...) as a boolean and runs only the first branch that evaluates to true.

Basic if, elseif, and else Structure

Chain elseif branches when checking mutually exclusive conditions, and finish with else as a fallback. Always wrap branch bodies in curly braces {} so adding a second line never breaks your logic.

<?php
declare(strict_types=1);

$score = 84;

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

echo "Student Grade: {$grade}" . PHP_EOL;

Ternary Expressions and Guard Clauses

For short two-way assignments, the ternary operator (condition ? trueValue : falseValue) keeps code concise. Inside functions, prefer early-return guard clauses instead of deeply nested if / else pyramids.

<?php
declare(strict_types=1);

function processOrder(array $order): string
{
    if (empty($order['items'])) {
        return "Rejected: Cart is empty.";
    }

    if (!($order['paid'] ?? false)) {
        return "Pending: Payment required.";
    }

    $shipping = $order['total'] >= 50 ? "Free" : "$6.99";
    return "Confirmed! Shipping: {$shipping}";
}

echo processOrder(['items' => ['Book'], 'paid' => true, 'total' => 65]) . PHP_EOL;

Common Mistakes to Avoid

• Nesting if statements four levels deep: Use early return or continue statements to keep functions shallow and easy to follow.
• Writing = instead of ===: An assignment inside if ($role = 'admin') always evaluates to truthy and overwrites $role.
• Using else after an early return: Once an if branch returns, the remaining code already acts as the else path.

Frequently Asked Questions

Is there any difference between elseif and else if in PHP?

Inside curly braces { ... }, both work identically. However, when using alternative colon syntax (if ($a): ... endif;), only single-word elseif is valid.

When should I use a ternary operator instead of a full if/else?

Use ternary expressions only for short, single-line value assignments. Avoid nested ternaries because they are hard to read and require explicit parentheses in PHP 8.

What values count as falsy inside a PHP if condition?

false, 0, 0.0, "", "0", empty arrays [], and null all evaluate to false in boolean context.