Get all array index in a specific range

Hi everybody,

I’m having a problem with arrays and their index, and I need to do something but I can’t figure out how to do it but I hope it’s possible, let me explain:

I have an array and I need to know how many index it contains whose number is in a specific range.
For example, I have an array of 10 elements and I need to get the amount of items between index >= 0 and <4.

Is it possible to do that? Thanks in advice.