[New-bugs-announce] [issue25192] deque append and appendleft should return value if maxlen set

[Alun Champion]

New submission from Alun Champion:

Currently if you append or appendleft when len(deque) == maxlen item from the other end of the deque is discarded. These should return the discarded value to allow you to write:

    x = deque.append(y)

vs

    if len(deque) == deque.maxlen():
        x = deque.pop()
    deque.append(y)

It should return None if len(deque) < maxlen or maxlen is not set.

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components: Library (Lib)
messages: 251154
nosy: Alun Champion
priority: normal
severity: normal
status: open
title: deque append and appendleft should return value if maxlen set

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Python tracker <report at bugs.python.org>
<http://bugs.python.org/issue25192>
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