Is there any sort of assign-if-not-empty-otherwise-assign-null function in PHP?
I'm looking for a cleaner alternative to the following:
$variable = (!empty($item)) ? $item : NULL;
It would also be handy if I could specify the default value; for instance, sometimes I'd like ' ' instead of NULL.
I could write my own function, but is there a native solution?
Thanks!
EDIT: It should be noted that I'm trying to avoid a notice for undefined values.
PHP 7 adds the null coalescing operator to handle assignment depending on whether the right hand side is set.
The null coalescing operator (??) has been added as syntactic sugar for the common case of needing to use a ternary in conjunction with isset(). It returns its first operand if it exists and is not NULL; otherwise it returns its second operand.
<?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';
?>
Additionally, PHP 7.4 adds the null coalescing assignment operator, which handles the opposite case -- assigning a value depending on whether the left hand side is set:
<?php
$array['key'] ??= computeDefault();
// is roughly equivalent to
if (!isset($array['key'])) {
$array['key'] = computeDefault();
}
?>
I ended up just creating a function to solve the problem:
public function assignIfNotEmpty(&$item, $default)
{
return (!empty($item)) ? $item : $default;
}
Note that $item is passed by reference to the function.
Usage example:
$variable = assignIfNotEmpty($item, $default);
isset instead of empty. The documentation also makes reference to isset. "In particular, this operator does not emit a notice or warning if the left-hand side value does not exist, just like isset()."Re edit: unfortunately, both generate notices on undefined variables. You could counter that with @, I guess.
In PHP 5.3 you can do this:
$variable = $item ?: NULL;
Or you can do this (as meagar says):
$variable = $item ? $item : NULL;
Otherwise no, there isn't any other way.
?:) generates notice if undefined ?
$variable = @$item ?: NULL; would be nicer.There's the null coalescing assignment operator (??=) that can be useful if you have a nullable parameter value and want to set a default if it's null.
function foo(?Bar $bar): void
{
$bar ??= new Bar();
}
Well yes, there is a native solution for assigning the value or NULL when the variable was unset:
$variable = $possibly_unset_var;
If you just want to suppress the notice (which doesn't solve anything or makes the code cleaner), there is also a native syntax for that.
$variable = @$unset_var;
I wouldn't recommend this on a production system, but:
<?php
//$value=1;
$item=@$value ?:null;
var_dump($item); // NULL
?>
<?php
$value=1;
$item=@$value ?:null;
var_dump($item); // 1
?>
$variablewhen$itemis empty.