PHP: Unidentified Index with NULL value

Question

I've tried everything but just can't get this notice to disappear.

I have a text input that display's the content of $variable which is being grabbed from a database and either has value of NULL or an integer value.

When the value is NULL, and I use this, I get 1 error of unidentified index.

if(isset($data['variable'])) { $variable = $data['variable']; }
else { $variable = numberFormat($data['variable']); } 

When the value is NULL, and I use this, I get 2 errors of unidentified index.

if($data['variable'] == NULL) { $variable = $data['variable']; } 
else { $variable = numberFormat($data['variable']); }

Can anyone shed some light to how to get rid of these "notices"? Thank you!

Answer 1

You might want to see if the $data variable is available. If that is null, then you can't access an element inside a non-existent variable.

if (isset($data)) {
    if(isset($data['variable'])) { $variable = $data['variable']; }
    else {
        //THIS MAKES NO SENSE. $data['variable'] does not exist.
        //$variable = numberFormat($data['variable']);
        //You can put something else in here, however
        $variable = "";
    } 
}

Secondly, accessing $data['variable'] when it does not exist is non-sensical because... well I doesn't exist!

Answer 2

I suppose $data['variable'] does not exist. You get 2 errors in the second example, because you didn't use isset(), which can handle unset variables.

Answer 3

null values aren't retrieved from a MySQL database, so any variable that might contain one is not set.

In your first snippet you're testing for this, but go ahead and assign the value anyway, so you get a notice.

if(isset($data['variable'])) {
  $variable = $data['variable'];
} else { 
  $variable = numberFormat($data['variable']); // Test for isset() fails, code comes here.
} 

You need to assign something meaningful to $variable in your else clause since $data['variable'] is not set.

Answer 4

Try

$variable = (isset($data['variable'])) ? $data['variable'] : 0;