If null use other variable in one line in PHP

Is there in PHP something similar to开发者_运维问答 JavaScript's:

alert(test || 'Hello');

So, when test is undefined or null we'll see Hello, otherwise - we'll see the value of test.

I tried similar syntax in PHP but it doesn't seem to be working right... Also I've got no idea how to google this problem..

thanks

Edit

I should probably add that I wanted to use it inside an array:

$arr = array($one || 'one?', $two || 'two?'); //This is wrong

But indeed, I can use the inline '? :' if statement here as well, thanks.

$arr = array(is_null($one) ? "one?" : $one, is_null($two) ? "two ?" : $two); //OK

you can do echo $test ?: 'hello';

This will echo $test if it is true and 'hello' otherwise.

Note it will throw a notice or strict error if $test is not set but...

This shouldn't be a problem since most servers are set to ignore these errors. Most frameworks have code that triggers these errors.

Edit: This is a classic Ternary Operator, but with the middle part left out. Available since PHP 5.3.

echo $test ? $test : 'hello'; // this is the same
echo $test ?: 'hello';        // as this one

This only checks for the truthiness of the first variable and not if it is undefined, in which case it triggers the E_NOTICE error. For the latter, check the PHP7 answer below (soon hopefully above).

From PHP 7 onwards you can use something called a coalesce operator which does exactly what you want without the E_NOTICE that ?: triggers.

To use it you use ?? which will check if the value on the left is set and not null.

$arr = array($one ?? 'one?', $two ?? 'two?'); 

See @Yamiko's answer below for a PHP7 solution https://stackoverflow.com/a/29217577/140413

 echo (!$test) ? 'hello' : $test;

Or you can be a little more robust and do this

echo isset($test) ? $test : 'hello'; 

As per the latest version use this for the shorthand

$var = $value ?? "secondvalue";

One-liner. Super readable, works for regular variables, arrays and objects.

// standard variable string
$result = @$var_str ?: "default";

// missing array element
$result = @$var_arr["missing"] ?: "default";

// missing object member
$result = @$var_obj->missing ?: "default";

See it in action: Php Sandbox Demo

I'm very surprised this isn't suggested in the other answers:

echo isset($test) ? $test : 'hello';

From the docs isset($var) will return false if $var doesn't exist or is set to null.

The null coalesce operator from PHP 7 onwards, described by @Yamiko, is a syntax shortcut for the above.

In this case:

echo $test ?? 'hello'; 

If you want to create an array this way, array_map provides a more concise way to do this (depending on the number of elements in the array):

function defined_map($value, $default) {
    return (!isset($value) || is_null($value)) ? $default : $value;
    // or return $value ? $default : $value;
}

$values = array($one, $two);
$defaults = array('one', 'two');

$values = array_map('defined_map', $values, $defaults);

Just make sure you know which elements evaluate to false so you can apply the right test.

Since php7.4, you can use the null coalescing assignment, so that you can do

$arr = array($one ??= "one?", $two ??= "two ?");

See the docs here

There may be a better way, but this is the first thing that came to my mind:

 echo (!$test) ? "Hello" : $test;

Null is false in PHP, therefore you can use ternary:

alert($test ? $test : 'Hello');

Edit:

This also holds for an empty string, since ternary uses the '===' equality rather than '=='

And empty or null string is false whether using the '===' or '==' operator. I really should test my answers first.

Well, expanding that notation you supplied means you come up with:

if (test) {
    alert(test);
} else {
    alert('Hello');
}

So it's just a simple if...else construct. In PHP, you can shorten simple if...else constructs as something called a 'ternary expression':

alert($test ? $test : 'Hello');

Obviously there is no equivalent to the JS alert function in PHP, but the construct is the same.

alert((test == null || test == undefined)?'hello':test);

I recently had the very same problem.This is how i solved it:

<?php if (empty($row['test'])) {
                    echo "Not Provided";} 
                        else {
                    echo $row['test'];}?></h5></span></span>
              </div>

Your value in the database is in variable $test..so if $test row is empty then echo Not Provided