Best way to check if array key exists and is empty string

Question

I have a setter in which I need to pass a value from an array-element with a specific key.

If the array key does not exist pass null
If the element value is an empty string '' pass null
If the value is not empty string 'string or int or ...' - pass the value

What I have is this:

$obj->setValue(isset($array['a']) ? (!empty(trim($array['a'])) ? $array['a'] : null ) : null );

Some would argue that its hard to read. So - whats the "clean" way?

$obj->setValue(trim($array['a']) ?: null); . This will throw PHP Notice if key does not exist, but PHP Notice should be suppressed on production environment — Anggara
– Anggara, Commented Jan 24, 2020 at 18:38

Alex Howansky · Accepted Answer · 2020-01-24 19:36:03Z

2

You can chain the null coalesce operator (which catches nulls and non-existing keys) with the empty ternary operator (which catches empty values):

$obj->setValue($array['a'] ?? null ?: null);

Example:

$array = [
    'a' => 'foo',
    'b' => '',
];
var_dump($array['a'] ?? null ?: null); // 'foo'
var_dump($array['b'] ?? null ?: null); // null
var_dump($array['c'] ?? null ?: null); // null

answered Jan 24, 2020 at 19:36

Alex Howansky

54k8 gold badges85 silver badges102 bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

Schmalitz Over a year ago

Excellent. I was close to that. But why is $array['b'] working? $array['b'] is existing so it should fire ''. Why is ?: executed though?

Alex Howansky Over a year ago

?? tests against null, which '' fails, so it passes through. ?: tests against empty, which '' passes so it triggers and returns null instead.

Collectives™ on Stack Overflow

Best way to check if array key exists and is empty string

1 Answer 1

2 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

2 Comments

Your Answer

Sign up or log in

Post as a guest

Related