How do get the array length?

What I find absolutely astounding is the attitude here.

often the teacher is limited by what they were taught that can and can not be done.

Sounds like a pretty good attribute for a teacher.
I mean, you wouldn't want to teach what can't be done, would you?

(I teach SCUBA diving. My store-bought gear will take me down, on air, to probably about 200 metres or a lot more. It's really ordinary quality gear. That would be really, really stupid, so I teach people not to do it. If people want to swim down past me, I will remonstrate with all the vehemence non-verbal communication allows, but I'm not going to go down after them much beyond about 45 metres)

programming experience, counts for very little when you can not be bothered to sit and explain why you think that something can not be done

It's not that I "think" it can't be done, it's way deeper than that.

What does not help is attitudes of people, especially moderators

We're human too. Get over it.

I am trying to learn what this device can do and come up with some of my own demonstrations and during the journey make a few discoveries as well as learn its limitations.

We had a similar evangelist a few days ago who exhorted us to try hooking up LEDs and trying stuff like analogWrite (LEDpin, 1023) and see how bright it was.
But was analogWrite (LEDpin, 1024) on a UNO any brighter? No, of course it wasn't.