PHP if, elseif and else Statements with Examples

if (condition) { ... } runs its block only when the condition is true. Add elseif (other condition) { ... } for more cases and else { ... } for everything left over. PHP checks the conditions from the top and runs only the first block that matches.

<?php
$temperature = 24;

if ($temperature >= 30) {
    echo "Hot";
} elseif ($temperature >= 20) {
    echo "Warm";
} elseif ($temperature >= 10) {
    echo "Cool";
} else {
    echo "Cold";
}

Change $temperature and run it again. Because the checks go from top to bottom, 24 stops at the second condition and never reaches >= 10, even though that is also true. Order your conditions from the most specific to the most general.

elseif vs else if

With curly braces, elseif and else if do the same thing. else if is technically an else whose body is a new if, but the result is identical.

<?php
$n = 0;

if ($n > 0) {
    echo "positive\n";
} elseif ($n < 0) {
    echo "negative\n";
} else {
    echo "zero\n";
}

if ($n > 0) {
    echo "positive\n";
} else if ($n < 0) {
    echo "negative\n";
} else {
    echo "zero\n";
}

The difference shows up only with the colon syntax used in templates (next sections). There, else if breaks the code:

<?php $score = 72; ?>
<?php if ($score >= 90): ?>
    <p>A</p>
<?php else if ($score >= 60): ?>
    <p>Passed</p>
<?php endif; ?>

PHP Parse error:  syntax error, unexpected token "if", expecting ":" in /home/index.php on line 4

Write elseif as one word and you never meet that error.

Multiple conditions with && and ||

&& (and) needs both sides to be true, || (or) needs at least one, and ! flips a condition. PHP stops evaluating as soon as the answer is known, so in $user !== null && $user['active'] the second part only runs when there is a user.

<?php
$age = 17;
$withParent = true;
$role = 'editor';

if ($age >= 18 || $withParent) {
    echo "Can enter\n";
}

if ($role === 'admin' || $role === 'editor') {
    echo "Can edit posts\n";
}

if (in_array($role, ['admin', 'editor'], true)) {
    echo "Same check, shorter\n";
}

if (!($age >= 18)) {
    echo "Not an adult\n";
}

When you mix && and ||, add parentheses: && binds tighter, and the parentheses make the intent obvious to the next reader. PHP also has and and or keywords, but they have a lower priority than =, so $ok = true and false; sets $ok to true. Stick to && and ||.

What counts as true in an if

The condition does not have to be a boolean. PHP converts it, and a handful of values count as false: false, 0, 0.0, "", "0", [] and null. Everything else is true, including "false", " " and "0.0".

That is why if ($items) is a common way to say "the array is not empty". The "0" row is the one that bites: a form field where someone typed 0 is a non-empty string, yet if ($_POST['qty']) treats it as false. Compare explicitly (if ($qty !== '')) when zero is a valid answer. The same rules decide what empty() returns.

<?php
$cart = [];
$quantity = "0";

if ($cart) {
    echo "Cart has items\n";
} else {
    echo "Cart is empty\n";
}

if ($quantity) {
    echo "Quantity given\n";
} else {
    echo "Treated as false, even though the user typed 0\n";
}

if ($quantity !== '') {
    echo "Explicit check: quantity is $quantity\n";
}

if else in HTML with if: and endif;

Between HTML tags, the curly braces are easy to lose. PHP has an alternative syntax: a colon after the condition, elseif ...: and else: for the other branches, and endif; at the end. Run this block, then click the scores in the Page tab: each link runs the same script again with a new $_GET['score'].

<?php
$score = (int) ($_GET['score'] ?? 72);
?>
<style>
    .pass { color: #1a7f37; } .fail { color: #cf222e; }
</style>
<h3>Score: <?= $score ?></h3>

<?php if ($score >= 90): ?>
    <p class="pass">Excellent, grade A.</p>
<?php elseif ($score >= 60): ?>
    <p class="pass">Passed.</p>
<?php else: ?>
    <p class="fail">Not passed yet. You need 60.</p>
<?php endif; ?>

<p>Try: <a href="?score=95">95</a> · <a href="?score=72">72</a> · <a href="?score=40">40</a></p>

<?= $score ?> is short for <?php echo $score; ?>. The same colon style exists for loops (foreach: endforeach;, while: endwhile;) and is what most PHP templates use.

One-line if and the ternary operator

A single statement may follow the condition without braces. It works, but the next line you add will not be inside the if, so many style guides require braces always. To pick one of two values, the ternary operator is shorter than a full if/else.

<?php
$count = 3;
$debug = false;

if ($debug) echo "Debug mode\n";

$label = $count === 1 ? 'item' : 'items';
echo "$count $label\n";

// Same thing with if/else
if ($count === 1) {
    $label = 'item';
} else {
    $label = 'items';
}
echo "$count $label\n";

When there are many exact values to compare against one variable, a match expression reads better than a long elseif chain.

Return early instead of nesting

Deeply nested if blocks are hard to follow. Inside a function, check the failure cases first and return right away. The main logic then sits at the left edge.

<?php
function checkout(array $cart, ?string $email): string
{
    if (!$cart) {
        return "Cart is empty";
    }
    if ($email === null) {
        return "Email required";
    }
    if (!filter_var($email, FILTER_VALIDATE_EMAIL)) {
        return "Invalid email";
    }

    return "Order placed for $email";
}

echo checkout([], 'ada@example.com'), "\n";
echo checkout(['book'], null), "\n";
echo checkout(['book'], 'not-an-email'), "\n";
echo checkout(['book'], 'ada@example.com'), "\n";

Common mistake: = instead of == in a condition

A single = assigns. if ($role = 'admin') stores 'admin' in $role and then tests that string, which is true. The block runs for every user, and $role is now wrong too.

<?php
$role = 'guest';

if ($role = 'admin') {
    echo "Bug: everyone is admin now, role is '$role'\n";
}

$role = 'guest';
if ($role === 'admin') {
    echo "Admin\n";
} else {
    echo "Fixed: role is '$role'\n";
}

Use === for comparisons unless you have a reason to want type juggling. Some people write the constant first (if ('admin' === $role)), so a missing = becomes an error instead of a silent assignment.