python-队列

class Quene():
    """队列"""
    def __init__(self):
        self.__list = []

    def enqueue(self,item):
        """往队列中添加元素"""
        self.__list.append(item)

    def dequeue(self):
        """从队列头部删除一个数据"""
        if self.__list:
            return self.__list.pop(0)
        else:
            return None

    def is_empty(self):
        """判断一个队列是否为空"""
        return  self.__list == []

    def size(self):
        """返回队列大小"""
        return len(self.__list)

if __name__ == '__main__':
    s = Quene()
    print(s.dequeue())
    s.enqueue(1)
    s.enqueue(2)
    s.enqueue(3)
    s.enqueue(4)
    print(s.dequeue())
    print(s.dequeue())
    print(s.dequeue())
    print(s.dequeue())
    print(s.is_empty())
    print(s.size())