如何在python中深度拷贝队列

Question

如何在python中深度拷贝队列？ 谢谢

Answer 1

不知道你确切的需求，但它可能是你会对我在DaniWeb关于优先级队列的讨论中发布的代码感兴趣。该列表是容易通过切片等

#Python 2.6.5 
from random import randint 
class Priority: 
    def __init__(self,prioritylevels=5): 
     """The constructor builds list for priority queue which would be used later 
     """ 
     self.prioritylevels = prioritylevels 
     self.pq = [[] for priority in range(self.prioritylevels)] # prioritylevels 

    def add_to_queue(self, data, priority=None): 
     """Add every received in data and use priority parameter or 
     its priority key to get its priority value (1 == highest) in the global queue 
     """ 
     if priority is None: priority = data['priority']-1 
     else: priority -= 1 

     if 0 <= priority < self.prioritylevels: 
      self.pq[priority].append(data) 
     else: raise ValueError,"Priority level out of bounds: %s" % priority 

    def get(self): 
     """ get lowest priority values first from queue """ 
     for priorityevents in self.pq: 
      while priorityevents: 
       yield priorityevents.pop(0) ## use list as queue to keep insertion order (remove from front)    
    def num_items(self): 
     return sum(len(q) for q in self.pq) 


if __name__ == '__main__': 

    myqueue = Priority(8) 
    for i in range(100000): 
     item=randint(0,234234) 
     if not i % 10000: print i, 
     priority=(item & 0b111) +1 ## lets three lowest bits decide which priority we give 
     myqueue.add_to_queue(('Number',item),priority=priority) 

    print "\n%i items in queues" % myqueue.num_items() 
    print "Items by priorities" 
    print '\n'.join("%i: %i" % (priority+1,len(q)) for priority, q in enumerate(myqueue.pq)) 
    print "\nGetting items out of queue in priority order:" 
    priority=0 
    for description,i in myqueue.get(): 
     assert (i & 0b111 >= priority), '** Bug ***' ## validity test priority must be same or lower for items 
     priority = i & 0b111 
    # empty after get 
    print "Finished" 
    print "%i items in queue" % myqueue.num_items() 

Answer 2

在Python的queue module用于线程之间的同步共享数据保存拷贝。这是而不是打算作为数据结构，它不支持复制（甚至不是浅拷贝）。

（有可能通过.get和.put构建一个队列的许多deepcopy的公司，但原有队列将被销毁。）

如果你想有一个队列（或堆栈）的数据结构，use a collections.deque 。如果您想要优先队列，请使用heapq module。该双层支持deepcopy。 heapq由列表支持，因此deepcopy也受支持。