✋ Update: This post was originally published on my blog decodingweb.dev, where you can read the latest version for a 💯 user experience. ~reza
PHP double question marks (??) – officially known as Null coalescing operator – is a convenient alternative to ternary expressions in conjunction with isset().
You might have seen the following expression in your Laravel or PHP projects:
$result = $value ?? $alternativeValue;
But what do two question marks mean in PHP?
The above expression returns its first operand ($value) if it exists and is not null; otherwise, it returns the second operand ($alternativeValue).
The above expression is equivalent to:
$result = isset($value) ? $value : $alternativeValue;
How to use PHP double question marks
Before the Null coalescing operator, you’d have to use a ternary operator with a call to isset():
$iceCreamFlavor = isset($_POST['flavor']) ? $_POST['flavor'] : 'vanilla';
Or as an if statement:
$iceCreamFlavor = 'vanilla';
if (isset($_POST['flavor'])) {
$iceCreamFlavor = $_POST['flavor'];
}
But with the Null coalescing operator, you can summarize it into:
$iceCreamFlavor =$_POST['flavor'] ?? 'vanilla';
You can also chain multiple operators:
$display_name = $first_name ?? $last_name ?? 'Anonymous';
The above code will return the first defined value among $first_name, $last_name, and Anonymous.
The Null coalescing operator has been added to PHP since version 7.
I hope you found this quick tip helpful 🙂
Thanks for reading!
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