Well yes, but ndarray is a library, which is what I said. You certainly don't get this "for free" in the language, which means you aren't forced to think this w

Well yes, but ndarray is a library, which is what I said. You certainly don't get this "for free" in the language, which means you aren't forced to think this way as a beginner in the language, which is why libraries like ndarray generally have a learning curve, in whatever language you find them. In J you have to get over that learning curve much earlier, because, as you said, the language is focused on it. (Which is the point the article is making, about how J changes the way you think. If you were writing an article about how Rust changes the way you think, I don't think you'd mention ndarray.)