while not leave: python
时间: 2023-10-14 18:57:27 浏览: 33
在Python中,`while`循环用于重复执行一段代码直到满足某个条件时才停止。在你提供的代码中,`while not leave:`表示当`leave`变量为`False`时,循环将一直执行。你可以在循环体内编写你想要重复执行的代码。当满足某个条件时,你可以将`leave`变量设置为`True`,以退出循环。
相关问题
queue python
A queue in Python is a linear data structure that follows the First-In-First-Out (FIFO) principle. It is similar to a real-life queue, where the first person to enter the queue is the first person to leave it.
In Python, a queue can be implemented using the built-in module 'queue'. There are two types of queues that can be created using this module: the 'Queue' class and the 'PriorityQueue' class.
The 'Queue' class is a basic queue that follows the FIFO principle. It has the following methods:
- put(item): Adds an item to the end of the queue.
- get(): Removes and returns the item at the front of the queue.
- empty(): Returns True if the queue is empty, False otherwise.
- qsize(): Returns the number of items in the queue.
The 'PriorityQueue' class is a queue that orders the items based on their priority. It has the same methods as the 'Queue' class, but it also has a 'put(item, priority)' method that allows the user to specify the priority of the item being added.
Here's an example of how to create and use a 'Queue' object in Python:
```
import queue
q = queue.Queue()
q.put(1)
q.put(2)
q.put(3)
while not q.empty():
print(q.get())
```
Output:
```
1
2
3
```
In this example, we create a 'Queue' object and add three items to it using the 'put' method. We then use a while loop to remove and print each item using the 'get' method. Since the queue follows the FIFO principle, the items are printed in the order they were added.
python简易停车场收费代码
好的,以下是一个简单的停车场收费 Python 代码示例:
```python
class ParkingLot:
def __init__(self, spots):
self.total_spots = spots
self.available_spots = spots
self.parking_slots = {}
def park(self, reg_number):
if self.available_spots == 0:
print("Sorry, parking lot is full.")
return False
else:
slot = self.total_spots - self.available_spots + 1
self.available_spots -= 1
print(f"Allocated slot number: {slot}")
self.parking_slots[slot] = reg_number
return True
def leave(self, slot):
if slot not in self.parking_slots:
print("Invalid slot number.")
return False
else:
self.available_spots += 1
del self.parking_slots[slot]
print(f"Slot number {slot} is free.")
return True
def status(self):
print("Slot No.\tRegistration No.")
for slot, reg_num in self.parking_slots.items():
print(f"{slot}\t\t{reg_num}")
def get_reg_numbers_for_color(self, color):
reg_numbers = []
for slot, reg_num in self.parking_slots.items():
if self.parking_slots[slot] == color:
reg_numbers.append(reg_num)
if reg_numbers:
print(", ".join(reg_numbers))
else:
print("Not found.")
def get_slot_numbers_for_color(self, color):
slot_numbers = []
for slot, reg_num in self.parking_slots.items():
if self.parking_slots[slot] == color:
slot_numbers.append(str(slot))
if slot_numbers:
print(", ".join(slot_numbers))
else:
print("Not found.")
def get_slot_number_for_reg_number(self, reg_number):
for slot, num in self.parking_slots.items():
if self.parking_slots[slot] == reg_number:
print(f"{slot}")
return
print("Not found.")
def main():
capacity = input("Enter parking lot capacity: ")
parking_lot = ParkingLot(int(capacity))
while True:
command = input("Enter command: ")
inputs = command.split()
if inputs[0] == "park":
parking_lot.park(inputs[1])
elif inputs[0] == "leave":
parking_lot.leave(int(inputs[1]))
elif inputs[0] == "status":
parking_lot.status()
elif inputs[0] == "registration_numbers_for_cars_with_colour":
parking_lot.get_reg_numbers_for_color(inputs[1])
elif inputs[0] == "slot_numbers_for_cars_with_colour":
parking_lot.get_slot_numbers_for_color(inputs[1])
elif inputs[0] == "slot_number_for_registration_number":
parking_lot.get_slot_number_for_reg_number(inputs[1])
elif inputs[0] == "exit":
break
else:
print("Invalid input")
if __name__ == "__main__":
main()
```
该停车场有以下功能:
- park <reg_number>:停车并分配空闲车位
- leave <slot>:从指定车位上离开车辆
- status:查看停车场状态,包括所有已占用车位的车牌号码和车位号码
- registration_numbers_for_cars_with_colour <color>:查找与指定颜色匹配的所有车牌号码
- slot_numbers_for_cars_with_colour <color>:查找与指定颜色匹配的所有车位号码
- slot_number_for_registration_number <reg_number>:查找与指定车牌号码匹配的车位号码
当输入 “exit” 时程序停止运行。