How do I use the ternary operator ( ? : ) in PHP as a shortcut for “if / else”?

PHP 5+

(condition) ? /* value to return if condition is true */ 
            : /* value to return if condition is false */ ;

syntax is not a “shorthand if” operator (the ? is called the conditional operator) because you cannot execute code in the same manner as if you did:

if (condition) {
    /* condition is true, do something like echo */
}
else {
    /* condition is false, do something else */
}

PHP 7+

As of PHP 7, this task can be performed simply by using the Null coalescing operator like this :

 <?php
// Fetches the value of $_GET['user'] and returns 'nobody'
// if it does not exist.
$username = $_GET['user'] ?? 'nobody';
// This is equivalent to:
$username = isset($_GET['user']) ? $_GET['user'] : 'nobody';

// Coalescing can be chained: this will return the first
// defined value out of $_GET['user'], $_POST['user'], and
// 'nobody'.
$username = $_GET['user'] ?? $_POST['user'] ?? 'nobody';
?>