python - 如何在Python中的线程中增加类字段？

Question

我正在尝试实现一个小花园示例。Garden 是一个具有 grow() 的类功能，检查每秒供应的水量。当水量超过某个阈值时，花园就会开出一些花。

这是我的第一次尝试:

花园课

import time

class Garden:
    def __init__(self):
        self.water = 0
        print("Garden built!")

    def grow(self):
        while self.water < 50:
            print("Water supplied: {0}".format(self.water))
            time.sleep(1)
        print("Produced 5 flowers!")

ma​​in.py

import time
from garden import Garden
from threading import Thread
from queue import Queue

def main():
    que = Queue()
    garden = Garden()
    thr = Thread(target=garden.grow).start()
    que_garden = que.get()
    water(que_garden, 20)
    time.sleep(5)
    water(que_garden, 30)
    thr.join()

def water(garden, amount):
    garden.water += amount
    print("Watered with {0}!".format(amount))

当我运行main.py时我得到以下输入:

Garden built!
Water supplied: 0
Water supplied: 0
Water supplied: 0
Water supplied: 0
Water supplied: 0

所以，grow()不断地接到电话，但从未接通water(que_garden, 20)线。我预料到了一次thr = Thread(target=garden.grow).start()被调用时它不会被锁定，直到 grow()完成但继续下一行。我在这里缺少什么？

Answer 1

这个:

que_garden = que.get()

阻塞，直到队列中有东西为止。但任何地方都没有 que_garden.put() 。

这无需队列即可工作:

import time
from garden import Garden
from threading import Thread

def main():
    garden = Garden()
    thr = Thread(target=garden.grow)
    thr.start()
    water(garden, 20)
    time.sleep(5)
    water(garden, 30)
    time.sleep(5)
    water(garden, 10)
    thr.join()

def water(garden, amount):
    garden.water += amount
    print("Watered with {0}!".format(amount))

main()

输出:

Garden built!
Water supplied: 0
Watered with 20!
Water supplied: 20
Water supplied: 20
Water supplied: 20
Water supplied: 20
Watered with 30!
Produced 5 flowers!
Watered with 10!