Validaing Multiple, Specific Form Fields with errors() - cakephp-3.0

Question

I am building a multi-step form input (a "wizard") where the user input parts of an entity over multiple form input views. At each step, I want to validate only the input data (not the entire entity).
My question is how to use error() with an array of field names.
The model has 12 fields with validation rules. I want to validate 3 of those in one controller action.
So, in this controller action, I get three inputs
$thedata = $this->request->data;
This results in:
['number' => '102','color' => 'blue','size' => 'large']
I then make an array of field names:
$thearray = array_keys($thedata);
This results in:
[
(int) 0 => 'number',
(int) 1 => 'color',
(int) 2 => 'size']
Now I would like to check these three fields for errors.
$errors = $this->Items->newEntity($this->request->data)->errors($thearray);
This results in checking ALL 12 fields with validation defined, not just the three in the array, and it fails validation (it picks up all the errors in the entity).
If I define only ONE field to check it works:
$errors = $this->Items->newEntity($this->request->data)->errors('number');
This correctly validates only the field 'number' and produces the desired result.
However, passing an array of fields instead of a string with a single field name validates ALL fields requiring validation.
Also, I tried hard-coding an array as a parameter of errors():
$errors = $this->Items->newEntity($this->request->data)->errors(['number','color']);
That also checks all 12 fields in the table definition, not just these two.
So the question is, how do you prepare the array and pass it to the errors() method if you want to check only two or three specific fields?
Thanks in advance for any advice!
D
Thanks in

Answer 1

According to the docs errors can take a $field argument, but not an array. If you want to validate multiple fields without validating all of them, you could loop over $thearray.
$item = $this->Items->newEntity($this->request->data);
foreach ($thearray as $error) {
$errors[] = $item->errors($error);
}