What is the PHP shorthand for: print var if var exist

php var isset
bart picture bart · Apr 29, 2011 · Viewed 28.7k times · Source

We've all encountered it before, needing to print a variable in an input field but not knowing for sure whether the var is set, like this. Basically this is to avoid an e_warning.

<input value='<?php if(isset($var)){print($var);}; ?>'>

How can I write this shorter? I'm okay introducing a new function like this:

<input value='<?php printvar('myvar'); ?>'>

But I don't succeed in writing the printvar() function.

Answer

NikiC picture NikiC · Apr 29, 2011

For PHP >= 5.x:

My recommendation would be to create a issetor function:

function issetor(&$var, $default = false) {
    return isset($var) ? $var : $default;
}

This takes a variable as argument and returns it, if it exists, or a default value, if it doesn't. Now you can do:

echo issetor($myVar);

But also use it in other cases:

$user = issetor($_GET['user'], 'guest');

For PHP >= 7.0:

As of PHP 7 you can use the null-coalesce operator:

$user = $_GET['user'] ?? 'guest';

Or in your usage:

<?= $myVar ?? '' ?>

Related questions

PHPDoc type hinting for array of objects?

So, in PHPDoc one can specify @var above the member variable declaration to hint at its type. Then an IDE, for ex. PHPEd, will know what type of object it's working with and will be able to provide a code …

Read More
What is /var/www/html?

I am starting to pick up PHP / MySQL, but in all the documentation I'm reading, it mentions /var/www/html as being the folder you want to install a framework such as CakePHP, or for example /var/www/html being …

Read More
Php: what's the difference between $var and &$var?

What is the difference between foreach ($my_array as $my_value) { } And: foreach ($my_array as &$my_value) { } ? May I ask you to give me two real-world examples of when to use one and when you use the other?

Read More