I think a tutorial on arrays should mention for loop since those are quite natural with a random access mutable structure. It would make sense to make the parallel between loops and iterators functions but not mentioning for seems quite partial in this case.
There is a typo in the subheader “Lenght of an array.”
You may also want to mention the functions Array.iteri and Array.mapi under the iterate and map sections. Those are often the functions I need, and someone coming from, say, Python who is used to enumerate() may not find those obvious.
There are a few typos in the paragraph under “Sorting an Array”:
an array Ir sorts the provided array in place, in ascending order, according to the provided comparison function. [The?] Sorting performed by Array.sort modifies the content of the provided array, that['s?] why it returns unit .
Complete example of a simple function that uses Arrays. Currently all examples are written in utop but I think it would be helpful to see how to put all things together in a small function inside a module. For example, reversing an array.
Comparison with lists. Especially considering that the List tutorial comes first. It might not be obvious which one to pick for folks without extensive knowledge of Computer Science, Software Engineering and OCaml runtime system.