如何在PHP中使用三元运算符（？:)作为“if / else”的简写？

Question

Based on the examples from this page, I have the working and non-working code samples below.

Working code using if statement:

if (!empty($address['street2'])) echo $address['street2'].'<br />';

Non-working code using ternary operator:

$test = (empty($address['street2'])) ? 'Yes <br />' : 'No <br />';

// Also tested this
(empty($address['street2'])) ? 'Yes <br />' : 'No <br />';

UPDATE
After Brian's tip, I found that echoing $test outputs the expected result. The following works like a charm!

echo (empty($storeData['street2'])) ? 'Yes <br />' : 'No <br />';

Answer 1

The

(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 */
}

In your example, you are executing the echo statement when the $address is not empty. You can't do this the same way with the conditional operator. What you can do however, is echo the result of the conditional operator:

echo empty($address['street2']) ? "Street2 is empty!" : $address['street2'];

and this will display "Street is empty!" if it is empty, otherwise it will display the street2 address.