python基础----实现队列

class Queue(object):
    def __init__(self):
        self.data_list = [] #定义一个字段（空数组）
    def init_queue(self):
        self.data_list = []  #初始化这个空数组

    def insert(self, data):
        self.data_list.append(data)

    def pop(self):
        if len(self.data_list) == 0:
            return None
        data = self.data_list[0]
        del self.data_list[0]
        return data

    def size(self):
        return len(self.data_list)

queue = Queue()
print queue.size()
queue.insert(1)
queue.insert(2)
queue.insert(3)
head = queue.pop()
print head
head = queue.pop()
print head
head = queue.pop()
print head
head = queue.pop()
print head