实现队列的创建、入队、出队、取队首元素、判断队列是否为空
时间: 2023-09-19 12:12:18 浏览: 48
1. 创建队列:
```python
class Queue:
def __init__(self):
self.queue = []
```
2. 入队:
```python
def enqueue(self, value):
self.queue.append(value)
```
3. 出队:
```python
def dequeue(self):
if not self.is_empty():
return self.queue.pop(0)
else:
return None
```
4. 取队首元素:
```python
def peek(self):
if not self.is_empty():
return self.queue[0]
else:
return None
```
5. 判断队列是否为空:
```python
def is_empty(self):
return len(self.queue) == 0
```
完整代码如下:
```python
class Queue:
def __init__(self):
self.queue = []
def enqueue(self, value):
self.queue.append(value)
def dequeue(self):
if not self.is_empty():
return self.queue.pop(0)
else:
return None
def peek(self):
if not self.is_empty():
return self.queue[0]
else:
return None
def is_empty(self):
return len(self.queue) == 0
```
使用示例:
```python
q = Queue()
q.enqueue(1)
q.enqueue(2)
q.enqueue(3)
print(q.queue) # [1, 2, 3]
print(q.dequeue()) # 1
print(q.peek()) # 2
print(q.is_empty()) # False
print(q.dequeue()) # 2
print(q.dequeue()) # 3
print(q.dequeue()) # None
print(q.is_empty()) # True
```