PHP POST array with empty and isset

Question

I have the following multiple checkbox selection:

Apple


        

Answer 1

1. If I don't select any of checkboxes and then submit form, does $_POST array contain an index called $_POST['fruit_list']

No, key fruit_list does not exist

To check if key exists in array better use array_key_exists because if you have NULL values isset returns false

But in your case isset is a good way

isset - Determine if a variable is set and is not NULL (have any value).

empty - Determine whether a variable is empty (0, null, '', false, array()) but you can't understand if variable or key exists or not

For example:

$_POST['test'] = 0;
print 'isset check: ';
var_dump(isset($_POST['test']));
print 'empty check: ';
var_dump(empty($_POST['test']));

$_POST['test'] = null;

print 'isset NULL check: ';
var_dump(isset($_POST['test']));

print 'key exists NULL check: ';
var_dump(array_key_exists('test', $_POST));

isset check: bool(true)
empty check: bool(true)
isset NULL check: bool(false)
key exists NULL check: bool(true)