在python中迭代双端队列

Question

Since a deque is a doubly linked list, I should be able to iterate through it in order without any performance cost compared to a list. However, the following will be much slower than iterating through a list

for i in range(0, len(d)):
    doSomethingWith(d[i])

Since each time it goes to d[i] starting at d[0] . How do I make it iterate properly?

Answer 1

You can directly iterate over the deque.

for i in d:
    doSomethingWith(i)

(see the examples in the documentation: https://docs.python.org/2/library/collections.html#collections.deque )

Answer 2

I used a while loop for deque iteration, as follows:

from collections import deque

lst = [1,2,4,8]
queue=deque(lst)

print(queue)

while queue:
    print('{}{}'.format("head: ",queue[0]))
    queue.popleft()

output:

deque([1, 2, 4, 8])
head: 1
head: 2
head: 4
head: 8