A for-in loop is: "For Constant in Array {}". How can it be a constant if its value changes each time through the loop?

Hello Jonathan.

Actually that word (the one that follows the word "for") can be anything you like.

The fact is that it creates a constant in that moment, when the loop executes, so that value is assigned to it.

Nothing changes, it gets executed n times depending on the things in the array.

Another thing I noticed:

It seems as if the constant used for the loop is ephemeral. If you try to call its value after running the loop, an error results.

If you declare a variable or constant with the same name used for the constant in the for-in loop, you can do so without resulting with an error.

I'm no expert in Swift or in any other language for that matter, but I hope these observations help.