当函数卡在ifelifelse的第一个块上时

Question

我试图编写一个小的pomodoro计时器，它使用一个while循环和if-elif-else语句来检查要启动哪个计时器

正如预期的那样，它从第一个if块开始，然后修改变量，我希望它在那之后进入elif块，但是它似乎卡在if块中。并且不会重复整个while循环代码

如何克服这个问题

import os
import time

pomodoro = ['Pomodoro', 1500]
short_break = ['Short Break', 300]
long_break = ['Long Break', 1800]
pomodori_count = 0

def countdown(time_frame):
    duration = time_frame[1]
    while duration:
        os.system('clear')

        mins, secs = divmod(duration, 60)
        timer = '{:02d}:{:02d}'.format(mins, secs)

        print(f"{time_frame[0]} | {timer}")
        time.sleep(1)
        duration -= 1

while True:
    last = ""

    if last != "Pomodoro":
        countdown(pomodoro)
        last = "Pomodoro"
        pomodori_count += 1
    elif pomodori_count % 4 != 0:
        countdown(short_break)
        last = "Short Break"
    else:
        countdown(long_break)
        last = "Long Break"

Answer 1

因此，这段代码的错误在于，您在while循环的每个重复中重置了last值，因此它永远不会在下一个循环中保持其状态

您应该在while循环之前声明变量以解决此问题

last = ""
while True:

    if last != "Pomodoro":
        countdown(pomodoro)
        last = "Pomodoro"
        pomodori_count += 1
    elif pomodori_count % 4 != 0:
        countdown(short_break)
        last = "Short Break"
    else:
        countdown(long_break)
        last = "Long Break"