無法使創建的 python function 返回一個值，然后我可以在另一個計算中使用該值

Question

我定義了一個 function 詢問您在工作日什么時候開始，以及一個 function 詢問您何時完成。 我現在正在嘗試定義一個 function 來計算它們之間的時間差，而我遇到的問題實際上是使用調用開始/完成函數的結果。

我很難理解如何讓 function 返回我想要的值，即當我調用 function 並添加 Monday 參數時，從而詢問具體在星期一開始工作的時間。 我不確定如何獲得類似“10:00”的結果，因此我可以在另一個 function 中使用該結果。

此外，我越深入編寫此代碼，我就越對如何區分日子感到困惑。 例如，我創建了一個 function，它詢問你什么時候開始，然后我將它與另一個 function 結合起來，它基本上在一周中的幾天循環。 我意識到我不知道如何將星期一的ask_start_time function 與星期四的ask_start_time function 分開。

我得到的錯誤是：

What time did you start on Monday?10:00
Traceback (most recent call last):
File "C:/Users/MM/PycharmProjects/pythonProject2/test.py", line 49, in <module>
start_datetime = datetime.datetime.strptime(mon, '%H:%M')
TypeError: strptime() argument 1 must be str, not None

代碼：

    for a in range(attempts):
        start = input(f'What time did you start on {day_name}?')
        validation = re.match("^([0-1]?[0-9]|2[0-3]):[0-5][0-9]$", start)
        if validation:
            break
        print('Please use a HH:MM format only.')
    else:
        print('25 wrong attempts and you still don\'t understand that it\'s HH:MM?!')

def ask_finish_time(day_name, attempts=25):
    for a in range(attempts):
        finish = input(f'What time did you finish on {day_name}?')
        validation = re.match("^([0-1]?[0-9]|2[0-3]):[0-5][0-9]$", finish)
        if validation:
            break
        print('Please use a HH:MM format only.')

def days():
    work_days = ["Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday", "Sunday"]
    start_times = {day: ask_start_time for day in work_days}
    print(start_times)

def time_diff(a, b):
    return b - a

ask_start_time('Monday')
start_datetime = datetime.datetime.strptime(ask_start_time, '%H:%M')
ask_finish_time('Monday')
finish_datetime = datetime.datetime.strptime(ask_finish_time, '%H:%M')
print(time_diff(start_datetime, finish_datetime))

Answer 1

def ask_start_time(day_name, attempts=25):
    for a in range(attempts):
        start = input(f'What time did you start on {day_name}?')
        validation = re.match("^([0-1]?[0-9]|2[0-3]):[0-5][0-9]$", start)
        if validation:
            return start
        print('Please use a HH:MM format only.')
    else:
        print('25 wrong attempts and you still don\'t understand that it\'s HH:MM?!')

def ask_finish_time(day_name, attempts=25):
    for a in range(attempts):
        finish = input(f'What time did you finish on {day_name}?')
        validation = re.match("^([0-1]?[0-9]|2[0-3]):[0-5][0-9]$", finish)
        if validation:
            return finish
        print('Please use a HH:MM format only.')

def days():
    work_days = ["Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday", "Sunday"]
    start_times = {day: ask_start_time for day in work_days}
    print(start_times)

def time_diff(a, b):
    return b - a

start = ask_start_time('Monday')
start_datetime = datetime.datetime.strptime(start, '%H:%M')
finish = ask_finish_time('Monday')
finish_datetime = datetime.datetime.strptime(finish, '%H:%M')
print(time_diff(start_datetime, finish_datetime))

Answer 2

問題是ask_start_time和ask_finish_time什么都不返回，或者沒有返回。 從這些函數返回解析的時間，您的代碼將起作用。

def ask_start/end_time(...):
    ...
    return start/finish