Stack: data is last in first out (LIFO) last in first out
Queue: data FIFO (FIFO) first in first out
The first is a list :( either analog stack can be simulated queue) a good to poor.
A container is a sequence listing, but also in the simulated stack operations, the speed comparison is possible.
When simulation stack operations, must append to pop. (Stack simulation time, excellent performance)
The In [228]: LL = List () the In [229]: ll.append ( 'Task. 1') the In [230]: ll.append ( 'task 2') the In [231]: ll.append ( 'task 3 ') the In [232]: ll.pop (0) Out [232]:' tasks. 1 ' the In [233]: ll.pop (0) Out [233]:' task 2 ' the In [234]: ll.pop (0) Out [234]: 'task 3'
Such simulation operation queue is very inefficient because every time you are out of the first element, the latter element index will change
Professional time required argument is O (n)
The second is collections.deque, that a simulated stack are excellent in the queue container sequence.
In addition to poor performance of a random access intermediate element of the object, time-consuming to O (n), but half of the sequence of operation of the vessel, take few accesses to the intermediate element.
Analog stack operations:
In [235]: from collections import deque
In [236]: q = deque?
Init signature: deque(self, /, *args, **kwargs)
Docstring:
deque([iterable[, maxlen]]) --> deque object
A list-like sequence optimized for data accesses near its endpoints.
File: /usr/local/Cellar/python/3.7.4/Frameworks/Python.framework/Versions/3.7/lib/python3.7/collections/__init__.py
Type: type
Subclasses:
In [237]: q = deque()
In [238]: q.append('任务1')
In [239]: q.append ( 'task 2')
the In [240]: q.append ( 'task. 3')
the In [241]: q.pop ()
Out [241]: 'tasks. 3'
the In [242 ]: q.pop ()
Out [242]: 'task 2'
the In [243]: q.pop ()
Out [243]: 'tasks. 1'
the In [244]: Q
Out [244]: the deque ([] )
Analog queue-operation:
In [246]: q.append ( 'Task. 1') the In [247]: q.append ( 'task 2') the In [248]: q.append ( 'task. 3') the In [249]: Q Out [ 249]: deque ([ 'task 1', 'task 2', 'task. 3']) the In [250]: q.popleft () Out [250]: 'task 1' the In [251]: q.popleft ( ) Out [251]: 'task 2' the In [252]: Q. popleft () Out [252]: 'task 3'
That is the two above can simulate the stack, and can simulate container sequence queue, described below is only a single analog stack or queue.
queue.LifoQueue can be seen from the simulation is literally out of the stack, LIFO. container sequence in the queue module, provides a lock statement to support multiple concurrent producers to consumers. Many examples of the class of the following modules typically used in communication between threads.