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在这里，我创建了一个模块。

class Employee:
    def __init__(self):
        self.name = input("Enter your name: ")
        self.account_number = int(input("Enter your account number: "))
    def withdraw(self):   # it receives values from for
        if withdraw1 > current_balance:
            print ("You have entered a wrong number: ")
        else:
            print ("The current balance is: ", current_balance - withdraw1)

import TASK2 # I am importing the module I created 

c = TASK2.Employee()
def for(self):
    c.withdraw1 = int(input("enter number: "))
    c.current_balance = int(input("Enter the current balance: "))
d = method(c.withdraw) # here I am trying to pass the values to withdraw
print (d)

我得到的问题是，虽然它要求值而不是给我答案，但它给了我无。

4

1 回答 1

2

这是我对您的代码的看法。

# TASK2.py
class Employee:
    def __init__(self):
        self.name = input("Enter your name: ")
        self.account_number = int(input("Enter your account number: "))

        # make sure you initialise your member variables!
        self.withdraw_val = 0            # withdraw1 is ambiguous, so I use withdraw_val instead
        self.current_balance = 0

    # receives values from for ### no it doesn't, right now, it GIVES values TO your "for" function
    def withdraw(self):   
        if self.withdraw_val > self.current_balance:   # remember to use "self." to
                                                       # access members within the class
            print ("You have entered a wrong number: ")
        else:
            # again, remember "self."
            print ("The current balance is: ", self.current_balance - self.withdraw_val)

# TASK2sub.py

import TASK2

c = TASK2.Employee()

def for_employee(employee): # (1) don't use "self" outside a class
                            # it's contextually unconventional
                            # (2) "for" is a keyword in Python, don't use it for naming
                            # variables/functions, it'll mess things up

    employee.withdraw_val = int(input("Enter value to withdraw: "))
    employee.current_balance = int(input("Enter the current balance: "))

    return employee.withdraw_val  # not entirely sure what you want to return
                              # but you should definitely return something
                              # if you're going to assign it to some variable


d = for_employee(c.withdraw()) # "for_employee" function needs a return statement
                               # ".withdraw()" method should also require a return statement
print(d)

注意：从现在开始，我将参考您的原始for功能for_employee。另请注意，我仍然对您要完成的工作感到困惑，并且很可能有一个更合适的名称。

由于您的原始for_employee函数没有返回任何内容，因此None默认情况下它会返回。（这解释了您看到的输出。）

我认为您误解了函数的一般工作方式。例如，

d = for_employee(c.withdraw())
print(d)

您对该.withdraw()方法的评论不准确。

“它从 for 接收值”

更准确地说，c.withdraw()将首先计算，然后将返回的任何内容for_employee作为参数传递给函数。该方法不是“从”接收值，而是withdraw“将值赋予”for_employee函数。

更合理的是

c.withdraw()         # on a line by itself, since it doesn't return anything
d = for_employee(c)  # pass the entire object, since you'll be using self.withdraw_val and whatnot

print(d)

另一个问题是传统命名。这是我在定义名为的函数时从 IDLE（使用 Python 3.7）得到的for

>>> def for(a): return a
SyntaxError: invalid syntax

同样，for是 Python 中的关键字，不要用它来命名变量、函数或类。

使用self，它不那么严重（但我可以看到它让你感到困惑）。self更像是类方法中使用的约定。但for_employee 不是类方法。所以按照惯例，参数不应该命名为self.

（我发现代码像意大利面条一样，如果您通过将for_employee方法移动到类本身来重构代码可能会受益。那么使用 . 就完全有意义了self。）

于 2018-11-13T17:14:35.350 回答