python - 如何打印队列前面的元素python 3？

Question

    import queue
    q = queue.Queue()
    q.put(5)
    q.put(7)

print(q.get()) 删除队列前面的元素。如何打印这个元素而不删除它？可以这样做吗？

Answer 1

Queue 对象有一个 collections.deque 对象属性。请参阅有关访问双端队列元素的 Python 文档以了解效率。如果您需要随机访问元素，列表可能是更好的用例。

import queue

if __name__ == "__main__":
    q = queue.Queue()
    q.put(5)
    q.put(7)

    """
    dir() is helpful if you don't want to read the documentation
    and just want a quick reminder of what attributes are in your object
    It shows us there is an attribute named queue in the Queue class
    """
    for attr in dir(q):
        print(attr)

    #Print first element in queue
    print("\nLooking at the first element")
    print(q.queue[0])

    print("\nGetting the first element")
    print(q.get())

    print("\nLooking again at the first element")
    print(q.queue[0])

注意:我已经缩写了 dir 迭代器的输出

>>>
put
put_nowait
qsize
queue
task_done
unfinished_tasks

Looking at the first element
5

Getting the first element
5

Looking again at the first element
7
>>>