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

StackOverflow https://stackoverflow.com/questions/1506527

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 />';
Was it helpful?

Solution

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.

OTHER TIPS

PHP 7+

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

echo !empty($address['street2']) ?? 'Empty';

Basic True / False Declaration

$is_admin = ($user['permissions'] == 'admin' ? true : false);

Conditional Welcome Message

echo 'Welcome '.($user['is_logged_in'] ? $user['first_name'] : 'Guest').'!';

Conditional Items Message

echo 'Your cart contains '.$num_items.' item'.($num_items != 1 ? 's' : '').'.';

The ternary operator is just a shorthand for and if/else block. Your working code does not have an else condition, so is not suitable for this.

The following example will work:

echo empty($address['street2']) ? 'empty' : 'not empty';

It's the Ternary operator a.k.a Elvis operator (google it :P) you are looking for. 

echo $address['street2'] ?: 'Empty';

It returns the value of the variable or default if the variable is empty.

Note that when using nested conditional operators, you may want to use parenthesis to avoid possible issues!

It looks like PHP doesn't work the same way as at least Javascript or C#.

$score = 15;
$age = 5;

// The following will return "Exceptional"
echo 'Your score is: ' . ($score > 10 ? ($age > 10 ? 'Average' : 'Exceptional') : ($age > 10 ? 'Horrible' : 'Average'));

// The following will return "Horrible"
echo 'Your score is: ' . ($score > 10 ? $age > 10 ? 'Average' : 'Exceptional' : $age > 10 ? 'Horrible' : 'Average');

The same code in Javascript and C# return "Exceptional" in both cases.

In the 2nd case, what PHP does is (or at least that's what I understand):

  1. is $score > 10? yes
  2. is $age > 10? no, so the current $age > 10 ? 'Average' : 'Exceptional' returns 'Exceptional'
  3. then, instead of just stopping the whole statement and returning 'Exceptional', it continues evaluating the next statement
  4. the next statement becomes 'Exceptional' ? 'Horrible' : 'Average' which returns 'Horrible', as 'Exceptional' is truthy

From the documentation: http://php.net/manual/en/language.operators.comparison.php

It is recommended that you avoid "stacking" ternary expressions. PHP's behaviour when using more than one ternary operator within a single statement is non-obvious.

Conditional Welcome Message

echo 'Welcome '.($user['is_logged_in'] ? $user['first_name'] : 'Guest').'!';

Nested PHP Shorthand

echo 'Your score is:  '.($score > 10 ? ($age > 10 ? 'Average' : 'Exceptional') : ($age > 10 ? 'Horrible' : 'Average') );

You can do this even shorter by replacing echo with <?= code ?>

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

This is useful especially when you want to determine, inside a navbar, whether the menu option should be displayed as already visited (clicked) or not:

<li<?=($basename=='index.php' ? ' class="active"' : '')?>><a href="index.php">Home</a></li>

Here are some interesting examples, with one or more varied conditions.

$value1 = '1';
$value2 = '2';
$value3 = '3';

// 1 Condition
$v1 = ($value1 == '1') ? TRUE : FALSE;
var_dump($v1);
echo "<br>";

// 2 Conditions
$v2 = ($value1 == '' ? TRUE : ($value2 == '2' ? TRUE : FALSE));
var_dump($v2);
echo "<br>";

// 3 Conditions
$v3 = ($value1 == '' ? TRUE : ($value2 == '' ? TRUE : ($value3 == '3' ? TRUE : FALSE)));
var_dump($v3);
echo "<br>";

// 4 Conditions
$v4 = ($value1 == '1') ? ($value2 == '2' ? ($value3 == '3' ? TRUE : 'FALSE V3') : 'FALSE V2') : 'FALSE V1' ;
var_dump($v4);
echo "<br>";

I think you used the brackets the wrong way. Try this:

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

I think it should work, you can also use:

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

There's also a shorthand ternary operator and it looks like this:

(expression1) ?: expression2 will return expression1 if it evaluates to true or expression2 otherwise.

Example:

$a = 'Apples';
echo ($a ?: 'Oranges') . ' are great!';

will return

Apples are great!

Since PHP 5.3, it is possible to leave out the middle part of the ternary operator. Expression expr1 ?: expr3 returns expr1 if expr1 evaluates to TRUE, and expr3 otherwise.

From the PHP Manual

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