Okay, so im reading a guide for ruby and I can't make sense of this code. Where did i come from. I see that n is passed to iterate through the block but I have no idea where I comes from. If I could get a full explanation and breakdown of how this code works that would be great!
class Array
def iterate!
self.each_with_index do |n, i|
self[i] = yield(n)
end
end
end
array = [1, 2, 3, 4]
array.iterate! do |n|
n ** 2
end
Some methods that are called with code blocks will pass more than one value to the block, so you end up with multiple block arguments (in your case the block arguments are n and i, which will hold the current item in the array (n) and the index of it (i)).
You can find out how many arguments a block will be passed by looking at the documentation for a method (here's the docs for each_with_index). It does look like the extra values come from nowhere at first, and it takes a little while to memorize what a block will be passed when different methods are called.