Comment by getnormality

I guess I don't know enough about enough other languages to make broad generalizations. Oh well, it's too late to edit now.

My impression is that JavaScript is another language like R that values flexibility a lot.

And yeah, I agree that R is rather casual about lists vs maps. It doesn't really care that maps are a great data structure in their own right. It just wants to slap names on list elements when it's convenient to access elements of the list by name.