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Comment by orlp | Hacker News Reader

I don't like `shift` as a name because it might give the impression the entire window shifts. Push increases the window size by one and pop decreases the window size by one (evicting the earliest pushed element).

In my mental model `shift` would move the entire window, it would be one push + one pop.

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Ok, but shift is the commonly used name for that operation, and pop commonly does something else than what you just described. If you could come up with a better word than shift that would be fine, but pop should be the inverse of push in my opinion. If you push, then pop, you should have the same data as you started with.

> If you push, then pop, you should have the same data as you started with.

That's the case for a LIFO queue, but not a FIFO queue. Both commonly use the push/pop nomenclature.

Ah I haven't seen that before. I must admit that I'm not in the literature side of things. Any time I've seen a queue in production it would use put/get or enqueue/dequeue and in Ruby scripts you'd use an array and use push/shift.

I would say that's not common but in fact I don't think I've ever seen both push() & pop() be used to refer to those operations on FIFO queues in any language. (And LIFO is a stack, the exact opposite of a queue.)

The terminology I've seen people use for FIFO instead is enqueue() and dequeue(). Or push_front(), pop_back(). Etc.

Unfortunately, pop means two different things then. For the python lists, it pops "from the right" but for TwoStackAgg it pops "from the left". That makes the code harder to grasp.

Maybe use popleft?

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