Question

Following up on this question and answer, I decided to accept boolean true and false only, and not even null from the input by other developer/ user.

$default = array(
    "category_id"   =>  null,
    "category"      =>  false,
    "randomise"     =>  false
);

$config = array(
    "category_id"   =>  17,
    "randomise"     =>  false, 
    "category"      =>  null
);

function process_array($default,$config)
{
    # Set empty arrays for error & items.
    $error = array();
    $items = array();

    # Loop the array.
    foreach($default as $key => $value)
    {
        if (is_bool($default[$key]) && isset($config[$key])) 
        {
            if ($config[$key] === null) $error[] = '"'. $key.'" cannot be null.';

            # Make sure that the value of the key is a boolean.
            if (!is_bool($config[$key])) 
            {
                $error[] = '"'. $key.'" can be boolean only.';
            }

        }

            if(isset($config[$key]) && !is_array($value))
            {
                $items[$key] = $config[$key];
            }
            elseif(isset($config[$key]) && is_array($value))
            {
                $items[$key] = array_merge($default[$key], $config[$key]);
            }
            else
            {
                $items[$key] = $value;
            }
        }

        # Give a key to the error array.
        $error = array("error" => $error);

        # Merge the processed array with error array.
        # Return the result.
        return array_merge($items,$error);
}

print_r(process_array($default,$config));

but result I get is,

Array
(
    [category_id] => 17
    [category] => 
    [randomise] => 
    [error] => Array
        (
        )

)

the result I am after,

Array
(
    [category_id] => 17
    [category] => 
    [randomise] => 
    [error] => Array
        (
         [0] => "category" cannot be null.
        )

)

So I thought this line below should work, but I don’t understand why it doesn’t. I tried to use is_null but still not working. Any idea what have I done wrong and how can I fix this?

if ($config[$key] === null) $error[] = '"'. $key.'" cannot be null.';

Answer 1

isset($config[$key]) returns false if the value is null. use array_key_exists (http://php.net/manual/function.array-key-exists.php) instead.