如何将函数结果作为类的参数？

Question

我有这个程序会询问用户有关参数并将其传输到课堂上，但我找不到方法。 我尝试将该函数作为参数，但没有奏效。

class Exam:
    def __init__(self, day, importance):
        self.day = day
    self.importance = importance


days = [
    "Monday",
    "Tuesday",
    "Wednesday",
    "Thursday",
    "Friday",
    "Saturday",
    "Sunday",
]


def is_important():
    for day in days:
        answer = input("Ìs " + day + " Important")
        if answer == "True":
            return True
        elif answer == "False":
            return False


is_important() 

mon = Exam("Monday",)
tue = Exam("Tuesday", )
wed = Exam("Wednesday", )
thu = Exam("Thursday", )
fri = Exam("Friday", )
sat = Exam("Saturday", )
sun = Exam("Sunday", )

print(mon.importance)
print(tue.importance)
print(wed.importance)
print(thu.importance)
print(fri.importance)
print(sat.importance)
print(sun.importance)

Answer 1

Exam 类将定义如下。 这里我们传递两个参数并将其分配给类成员，我们还在其中定义了is_important类并分配了重要性变量

class Exam:
    def __init__(self, day, importance):
        self.day = day
        self.importance = importance

    def is_important(self):

        answer = input("Ìs " + day + " Important")
        if answer == "True":
            self.importance = True
        else:
            self.importance = False

然后您可以使用单个对象来分配重要性并打印它

mon = Exam("Monday", "True")
print(mon.day)
print(mon.importance)
tue = Exam("Tueday", "False")
print(tue.day)
print(tue.importance)
#Monday
#True
#Tueday
#False

或者只是循环到几天，然后每天调用is_important

days = [
    "Monday",
    "Tuesday",
    "Wednesday",
    "Thursday",
    "Friday",
    "Saturday",
    "Sunday",
]

exam_days = []
for day in days:
    exam_day = Exam(day)
    exam_day.is_important()
    exam_days.append(exam_day)

for exam_day in exam_days:
    print(exam_day.day)
    print(exam_day.importance)

输出将是

Ìs Monday Important True
Ìs Tuesday ImportantFalse
Ìs Wednesday ImportantFalse
Ìs Thursday ImportantTrue
Ìs Friday ImportantFalse
Ìs Saturday ImportantFalse
Ìs Sunday ImportantTrue
Monday
False
Tuesday
False
Wednesday
False
Thursday
True
Friday
False
Saturday
False
Sunday
True

Answer 2

is_important()应该将日期作为参数。 然后你可以用不同的日期调用它，并将结果传递给类。

def is_important(day):
    answer = input("Ìs " + day + " Important")
    return answer.lower() == "true"

mon = Exam("Monday", is_important("Monday");
tue = Exam("Tueday", is_important("Tuesday");
...

每天使用字典而不是单独的变量可能更好。 然后你可以这样做：

exam_days = {day: Exam(day, is_important(day)) for day in days}

Answer 3

实现这一点的最佳方法是使 is_important 成为类方法。 这更像是 Pythonic，并且在问题和工作日之间建立了明确的联系。 从本质上讲，它更面向对象，因为重要性和要求都与考试对象明确相关。 它是这样的：

class Exam:
    def __init__(self, day):
        self.day = day
        self.is_important()

    def is_important(self):
        answer = input("Ìs " + self.day + " Important? ")
        if answer == "Yes":
            self.importance = True
        elif answer == "No":
            self.importance = False

然后只需在循环中为每一天初始化 Exam 对象并将结果添加到字典中。 字典的优点是，您可以初始化多个变量，而无需键入额外的行，以便它们具有清晰的变量名称。 如果您有许多相同类型的对象，字典的键是比普通变量名更好的选择。

days = ["Monday", "Tuesday", "Wednesday", "Thursday",
        "Friday", "Saturday", "Sunday"]

my_week = {}

for day in days:
    my_week.update({day: Exam(day)})
    print my_week[day].importance

Answer 4

在考虑这个问题时，这可能是您想要考虑的一种方法，如果您想通过 Exam 对象携带改变重要性的能力：

class Exam:

    # COMMENT: set a default importance of False...
    def __init__(self, day, importance=False):
        self.day = day
        self.importance = importance

    # COMMENT: since you provide the day when the object is created,
    #     use that value (ie, self.day) in the input function call
    #     and overwrite the existing self.importance value.
    def is_important(self):
        answer = input("Ìs " + self.day + " Important?")
        if answer == "True":
            self.importance = True
        elif answer == "False":
            self.importance = False

# COMMENT: When you call the Class, you can provide it with the day 
#     and immediately provide it with an importance level.

mon = Exam("Monday", True)
tue = Exam("Tuesday", False)

# COMMENT: but you also have the flexibility to call the class and accept
#     the default importance OR overwrite it later by calling the 
#     is_important() method
wed = Exam("Wednesday")
wed.is_important()

print(mon.importance)
print(tue.importance)
print(wed.importance)