Question

How to reverse a queue in Python

Answer 1

from queue import Queue  
  
def printQueue(queue):
    i = 0
    while (i != queue.qsize()): 
        print(queue.queue[i]) 
        i = i + 1 
  
def reverseQueue(queue): 
    lst = []  
    while (not queue.empty()):  
        lst.append(queue.queue[0])  
        queue.get() 
    while (len(lst) != 0):  
        queue.put(lst[-1])  
        lst.pop() 
  
queue = Queue() 
    
queue.put(1)  
queue.put(2)  
queue.put(3)  
queue.put(4)  
queue.put(5)  

reverseQueue(queue)  

printQueue(queue) 
 
      
     
'''
run:

5
4
3
2
1
     
'''

 

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Answer 2

from queue import Queue  
   
def reverseQueue(queue): 
    lst = []  
    while (not queue.empty()):  
        lst.append(queue.queue[0])  
        queue.get() 
    while (len(lst) != 0):  
        queue.put(lst[-1])  
        lst.pop() 
   
q = Queue() 
     
q.put(1)  
q.put(2)  
q.put(3)  
q.put(4)  
q.put(5)  
 
reverseQueue(q)  
 
print(list(q.queue)) 
  
       
      
'''
run:
 
[5, 4, 3, 2, 1]
      
'''

 

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Answer 3

from queue import Queue  
   
def reverseQueue(queue): 
    lst = []  
    while (not queue.empty()):  
        lst.append(queue.queue[0])  
        queue.get() 
    while (len(lst) != 0):  
        queue.put(lst[-1])  
        lst.pop() 
   
q = Queue() 
     
q.put(1)  
q.put(2)  
q.put(3)  
q.put(4)  
q.put(5)  
 
reverseQueue(q)  
 
for item in q.queue:
    print(item)
  
       
      
'''
run:
 
5
4
3
2
1
      
'''

 

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