本文实例讲述了Python实现优先级队列的方法。分享给大家供大家参考,具体如下:
问题:要实现一个队列,它能够以给定的优先级对元素排序,且每次pop操作时都会返回优先级最高的那个元素;
解决方案:采用heapq模块实现一个简单的优先级队列
# example.py # # Example of a priority queue import heapq class PriorityQueue: def __init__(self): self._queue = [] self._index = 0 def push(self, item, priority): heapq.heappush(self._queue, (-priority, self._index, item)) self._index += 1 def pop(self): return heapq.heappop(self._queue)[-1] # Example use class Item: def __init__(self, name): self.name = name def __repr__(self): return 'Item({!r})'.format(self.name) q = PriorityQueue() q.push(Item('foo'), 1) q.push(Item('bar'), 5) q.push(Item('spam'), 4) q.push(Item('grok'), 1) print("Should be bar:", q.pop()) print("Should be spam:", q.pop()) print("Should be foo:", q.pop()) print("Should be grok:", q.pop())