How to do the shorthand conditional ternary in PHP

Most programmers are familiar with ternary operators. While most languages have their own shorthand conditional syntax, PHP added support for a shorter form in PHP 5.3 — letting you leave out the middle operand entirely. This shorthand is often called the Elvis operator (?:) because ?: vaguely resembles Elvis Presley's hair and raised eyebrow.

Let's walk through every form of a PHP conditional, from longest to shortest, and then look at the edge cases you need to understand to use ?: safely.

1. The Traditional if / else

<?php

$a = false;
$b = 'b';

if ($a) {
  echo $a;
} else {
  echo $b;
}

This is the most explicit form — clear, but verbose.

2. The Standard Ternary Operator

<?php

$a = false;
$b = 'b';

echo $a ? $a : $b;

The ternary operator takes three operands: the condition, the value if true, and the value if false. When the condition is truthy, the middle operand is returned; otherwise the right-hand operand is used.

3. The Shorthand Elvis Operator (?:)

<?php

$a = false;
$b = 'b';

echo $a ?: $b;

Since PHP 5.3, you can omit the middle operand. The expression $a ?: $b is equivalent to $a ? $a : $b — if $a is truthy, it is returned as-is; otherwise $b is returned. This avoids repeating $a twice, making the intent cleaner.

Practical Use Case: Default Values in Templates

One of the most common places you'll find ?: is in template or view files, where you want to fall back to a sensible default when a variable is empty or unset.

<span>Hello there, <?php echo $fullName ?: 'Guest' ?></span>

This prints the user's full name if it's a non-empty, truthy string — and falls back to "Guest" otherwise. Without ?:, you'd need a full if / else block or repeat the variable in a ternary, cluttering the template.

A few more real-world patterns:

<?php

// Use a config value, or fall back to a hard-coded default
$timeout = $config['timeout'] ?: 30;

// Use the first non-empty item in a list
$displayName = $user->nickname ?: $user->firstName ?: $user->email;

Edge Cases: Falsy Values to Watch Out For

Because ?: tests for truthiness — not merely for null — it will fall through to the right-hand side for any falsy value, including:

This matters in practice. If $count holds a legitimate value of 0, then $count ?: 'none' will incorrectly return 'none':

<?php

$count = 0;
echo $count ?: 'none'; // Outputs: none  ← probably not what you wanted!

In cases like this, you need the full ternary or an explicit isset / is_null check.

Elvis (?:) vs. Null Coalescing (??) — Know the Difference

PHP 7.0 introduced the null coalescing operator ??, which is often confused with ?:. They are not the same:

<?php

$value = 0;

var_dump($value ?: 'default');  // string(7) "default"  — 0 is falsy
var_dump($value ?? 'default');  // int(0)               — 0 is not null

Another key difference: ?? will not emit an E_NOTICE (or E_WARNING in PHP 8) when the left-hand variable is undefined, making it safer for reading from $_GET, $_POST, or optional array keys:

<?php

// Safe — no notice even if 'name' key is absent
$name = $_GET['name'] ?? 'Anonymous';

// Risky — triggers a notice if 'name' key is absent
$name = $_GET['name'] ?: 'Anonymous';

Rule of thumb: use ?? when your concern is null or missing; use ?: when you want to catch all falsy values and you know the variable is defined.

When to Avoid ?:

• Numeric inputs that can legitimately be 0 — use ?? or a strict check instead.
• Chained ternaries — PHP's ternary operator is left-associative, which leads to confusing results when you nest them. Prefer explicit if/else or separate statements.
• Arrays that might be empty but valid — an empty array [] is falsy, so $items ?: [] will always return [] even when $items is already [].

Quick Reference

<?php

// Long form
if ($a) { $result = $a; } else { $result = $b; }

// Standard ternary
$result = $a ? $a : $b;

// Elvis (shorthand ternary) — PHP 5.3+
$result = $a ?: $b;

// Null coalescing — PHP 7.0+
$result = $a ?? $b;

Understanding the distinction between these three forms means you can pick the right tool for each situation and avoid subtle bugs caused by PHP's type coercion rules.