Python中的并行while循环

Question

我刚接触Python，也刚开始学习编程，正在为我妹妹制作一个虚拟宠物风格的游戏。

在Python中，有办法让两个while循环同时运行吗？比如：

while 1:
    input_event_1 = gui.buttonbox(
        msg = 'Hello, what would you like to do with your Potato Head?',
        title = 'Main Screen',
        choices = ('Check Stats', 'Feed', 'Exercise', 'Teach', 'Play', 'Go to Doctor', 'Sleep', 'Change Favourite Thing', 'Get New Toy', 'Quit'))
    if input_event_1 == 'Check Stats':
        myPotatoHead.check_p_h_stats()
    elif input_event_1 == 'Feed':
        myPotatoHead.feed_potato_head()
    elif input_event_1 == 'Exercise':
        myPotatoHead.exercise_potato_head()
    elif input_event_1 == 'Teach':
        myPotatoHead.teach_potato_head(myPotatoHead)
    elif input_event_1 == 'Play':
        myPotatoHead.play_with_toy()
    elif input_event_1 == 'Sleep':
        myPotatoHead.put_p_h_asleep()
    elif input_event_1 == 'Go to Doctor':
        myPotatoHead.doctor_check_up()
    elif input_event_1 == 'Change Favourite Thing':
        myPotatoHead.change_favourite_thing()
    elif input_event_1 == 'Quit':
        input_quit = gui.ynbox(
            msg = 'Are you sure you want to quit?',
            title = 'Confirm quit',
            choices = ('Quit', 'Cancel'))
        if input_quit == 1:
            sys.exit(0)

while 1:
    time.sleep(20)
    myPotatoHead.hunger = str(float(myPotatoHead.hunger) + 1.0)
    myPotatoHead.happiness = str(float(myPotatoHead.happiness) - 1.0)
    myPotatoHead.tiredness = str(float(myPotatoHead.tiredness) + 1.0)

如果不行，有没有办法把这两个循环合成一个呢？我希望第二个循环里的内容每20秒发生一次，而第一个循环里的内容则是一直在进行的。

谢谢大家的帮助！

Answer 1

把其中一个放到一个函数里，threading.Thread 类支持一个叫做 target 的属性：

import threading
threading.Thread(target=yourFunc).start()

这会让你的函数 yourFunc() 在后台运行。

Answer 2

你应该使用状态机来处理这个问题（可以参考Apress的pygame书籍 - 下载链接在这里: http://apress.com/book/downloadfile/3765），具体内容在第七章。

下面是一个简化版的状态机：

def do_play(pet, time_passed):
    pet.happiness += time_pass*4.0

def do_feed(pet, time_passed):
    pet.hunger -= time_passed*4.0

def do_sleep(pet, time_passed):
    pet.tiredness += time_passed*4.0
    if pet.tiredness <= 0:
        return 'Waiting'

def do_waiting(pet, time_passed):
    pass

def do_howl(pet, time_passed):
    print 'Hoooowl'

def do_beg(pet, time_passed):
    print "I'm bored!"

def do_dead(pet, time_passed):
    print '...'

STATE_TO_FUNC = dict(Waiting=do_waiting,
                     Sleeping=do_sleep,
                     Feeding=do_feed,
                     Playing=do_play,
                     Howling=do_howl,
                     Begging=do_beg,
                     Dead=do_dead
                     )

class Pet:
    def __init__(self):
        self.state = 'Waiting'
        self.hunger = 1.0
        self.tiredness = 1.0
        self.happiness = 1.0

    def process(self, time_passed):
        self.hunger +=1*time_passed
        self.tiredness +=1*time_passed
        self.happiness -= 1*time_passed

        func = STATE_TO_FUNC[self.state]
        new_state = func(self, time_passed)
        if new_state is not None:
            self.set_state(new_state)

        if self.hunger >10:
            self.set_state('Dead')
        elif self.hunger > 5 and not (self.state == 'Feeding'):
            self.set_state('Howling')
        elif self.tiredness > 5:
            self.set_state('Sleeping')
        elif self.happiness < 0 and not (self.state == 'Playing'):
            self.set_state('Begging')

    def set_state(self,state):
        if not self.state == 'Dead':
            self.state = state

from msvcrt import getch
import time
pet = Pet()
while True:
    time0 = time.time()
    cmd = getch() # what command?
    pet.process(time.time()-time0)
    if cmd == 'a':
        pet.set_state('Feeding')
    if cmd == 's':
        pet.set_state('Sleeping')
    if cmd == 'd':
        pet.set_state('Playing')

Answer 3

你可以看看这个链接：Threading.Timer。

这里有一个链接：代码示例，教你如何每5秒运行一次一个函数。

import thread
import threading

class Operation(threading._Timer):
    def __init__(self, *args, **kwargs):
        threading._Timer.__init__(self, *args, **kwargs)
        self.setDaemon(True)

    def run(self):
        while True:
            self.finished.clear()
            self.finished.wait(self.interval)
            if not self.finished.isSet():
                self.function(*self.args, **self.kwargs)
            else:
                return
            self.finished.set()

class Manager(object):

    ops = []

    def add_operation(self, operation, interval, args=[], kwargs={}):
        op = Operation(interval, operation, args, kwargs)
        self.ops.append(op)
        thread.start_new_thread(op.run, ())

    def stop(self):
        for op in self.ops:
            op.cancel()
        self._event.set()

if __name__ == '__main__':
    # Print "Hello World!" every 5 seconds

    import time

    def hello():
        print "Hello World!"

    timer = Manager()
    timer.add_operation(hello, 5)

    while True:
        time.sleep(.1)