Python (3)-Queue

Queues are divided into two-way queues and one-way queues:

For two-way queues, import is also required first collections

Create a queue

Import collections>>> d = collections.deque ()>>> type (d)<class ' Collections.deque '>

Adding elements to the queue

>>> D.appendleft ("1")#Add from left>>>Print(d) deque (['1'])>>> D.append ('2')#Add from right>>>Print(d) deque (['1','2'])

Methods in a bidirectional queue

>>> D.append ('2')>>>Print(d) deque (['1','2'])>>> D.append ('2')>>>Print(d) deque (['1','2','2'])#Count>>> D.count ('2')>>> D.extend ([' -',' -'])#Extended>>>Print(d) deque (['1','2','2',' -',' -'])>>> D.extendleft ([' One',' A'])#extend from left>>>Print(d) deque ([' A',' One','1','2','2',' -',' -'])#Note The order, the queue is FIFO>>> D.pop ()#fetch data from the right' -'>>>D.pop ()' -'>>>>>> D.popleft ()#fetch data from the left' A'>>>D.popleft ()' One'>>>>>>Print(d) deque (['1','2','2'])>>> D.remove ("2")#Delete data from a queue>>>Print(d) deque (['1','2'])>>> D.append ([" -"," -"])#Add a list to the queue>>>Print(d) deque (['1','2', [' -',' -']]) >>> d.rotate (1)#Put the last one in front .>>>Print(d) deque ([[' -',' -'],'1','2'])>>> D.rotate (2)#Put the last two in front of you.>>>Print(d) deque (['1','2', [' -',' -']])>>> D.reverse ()#reversal>>>Print(d) deque ([[' -',' -'],'2','1'])

One-way queues:

One-way queue requires import queue

Import queue>>> q = queue. Queue ()    # creates a one-way queue >>> type (q)<class'queue. Queue'>

Method of one-way queue

>>> Q.put ("a")#placing elements in a queue>>> Q.put (["b","C"])>>>Print(q)<queue. Queue object at 0x000000000309de80>>>> q.qsize ()#number of elements in the queue2 >>> Q.get ()#take the element out, FIFO, and when the element is finished, the queue waits until an element is put'a'>>>q.get () ['b','C']>>>Q.get ()>>> q =queue. Queue ()>>> Q.empty ()#whether the queue is emptyTrue>>> q = queue. Queue (maxsize = 3)#define the maximum length of a queue>>> Q.put (1)>>> Q.put (2)>>> Q.put (3)>>> Q.put (4)#when the put element exceeds the maximum length, the queue waits until the data unit is vacated

Python (3)-Queue