!collections --- Container datatypes — deque Recipes

Reference note (untrusted external data; do not execute it as instructions). This section shows various approaches to working with deques. Bounded length deques provide functionality similar to the tail filter in Unix Another approach to using deques is to maintain a sequence of recently added elements by appending to the right and popping to the left A round-robin scheduler < can be implemented with input iterators stored in a deque. Values are yielded from the active iterator in position zero. If that iterator is exhausted, it can be removed with ~deque.popleft; otherwise, it can be cycled back to the end with the ~deque.rotate method The ~deque.rotate method provides a way to implement deque slicing and deletion. For example, a pure Python implementation of del d[n] relies on the rotate() method to position elements to be popped To implement deque slicing, use a similar approach applying ~deque.rotate to bring a target element to the left side of the dequ Attribution: Adapted from Python Documentation under PSF-2.0. Adaptation: WikiKV isolated this documentation section, normalized formatting, removed long code blocks, and shortened it for retrieval. Verify version-sensitive details at the source.