类继承问题-Python

Question

我是python的新手，在继承类方面遇到了麻烦。 这是对计算机编程课的在线介绍，我没有资源来弄清楚我的代码出了什么问题。 这是代码：

class Employee:
    def __init__(self, employeeName, employeeShift):
        self.__name = employeeName
        self.__number = employeeShift

    def set_name(self, nam):
        self.__name = nam

    def set__number(self, num):
        self.__number = num

    # Accessor methods
    def get_name(self):
        return self.__name

    def get_number(self):
        return self.__number

# ProductionWorker class that inherited the Employee class
class ProductionWorker(Employee):
    def __init__(self, shift, payRate):
        self.__shift_number = shift
        self.__pay_rate = payRate

    def set_shift_number(self, shift):
        self.__shift_number = shift

    def set_pay_rate(self, pay):
        self.__pay_rate = pay

    # Accessor methods
    def get_shift(self):
        return self.__shift

    def get_shift(self):
        if self.__shift_number = '1':
            s = 'Day shift'
        else self.__shift_number = '2':
            s = 'Night shift'
        return s 

    def get_pay(self):
        return self.__pay

    def get_pay(self):
        if self.__pay_rate <= 5:
            p = 7.50
        elif self.__pay_rate > 5 and self.__pay_rate <= 15:
            p = 13.50
        else self.__pay_rate >= 20:
            p = 20
        return p

# main module
def main():
    # Prompts the user for employee name, shift and pay rate
    employeeName = raw_input("Please enter the employee name: ")
    print "Please enter which shift the employee works."
    employeeShift = input("1 for day shift, 2 for night shift: ")
    payRate = input("How long has the employee worked here? ")

    # Creates object of ProductionWorker
    worker = ProductionWorker(employeeName, employeeShift, payRate)

    # Displays information
    print "Employee name:", worker.get_name()
    print "Employee shift:", worker.get_shift()
    print "Employee pay rate:", worker.get_pay_rate()

# calls main module
main()

它告诉我在我拥有self.__shift_number = '1'的def get_shift()下， ProductionWorker类中存在语法错误。 我按照我教授的例子，所以我不太了解这个错误。

Answer 1

Python使用==进行比较测试：

if self.__shift_number == '1':

=如果用于变量分配。

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编辑：

您实际上还有更多问题。 在开始学习之前，这是您脚本的固定版本：

class Employee:
    def __init__(self, employeeName, employeeShift):
        self.name = employeeName
        self.number = employeeShift

    def set_name(self, nam):
        self.name = nam

    def setnumber(self, num):
        self.number = num

    # Accessor methods
    def get_name(self):
        return self.name

    def get_number(self):
        return self.number

# ProductionWorker class that inherited the Employee class
class ProductionWorker(Employee):
    ##############################################
    def __init__(self, name, shift, payRate):
        self.name = name
    ##############################################
        self.shift_number = shift
        self.pay_rate = payRate

    def set_shift_number(self, shift):
        self.shift_number = shift

    def set_pay_rate(self, pay):
        self.pay_rate = pay

    # Accessor methods
    def get_shift(self):
       if self.shift_number == 1:
            s = 'Day shift'
       ###################################
       elif self.shift_number == 2:
       ###################################
            s = 'Night shift'
       return s 

    def get_pay(self):
        if self.pay_rate <= 5:
            p = 7.50
        elif self.pay_rate > 5 and self.pay_rate <= 15:
            p = 13.50
        ###################################
        elif self.pay_rate >= 20:
        ###################################
            p = 20
        return p

# main module
def main():
    # Prompts the user for employee name, shift and pay rate
    employeeName = raw_input("Please enter the employee name: ")
    print "Please enter which shift the employee works."
    employeeShift = input("1 for day shift, 2 for night shift: ")
    payRate = input("How long has the employee worked here? ")

    # Creates object of ProductionWorker
    worker = ProductionWorker(employeeName, employeeShift, payRate)

    # Displays information
    print "Employee name:", worker.get_name()
    print "Employee shift:", worker.get_shift()
    print "Employee pay rate:", worker.get_pay()

# calls main module
main()

现在这是我所做的：

1. 用elif替换了所有else （因为else不支持条件）。

2. 除了__init__的那些，我删除了每个双下划线。 这是因为双下划线在像这样使用时在Python中具有特殊的含义。

3. 向ProductionWorker.__init__添加了一个name参数（因为您在此行中输入了一个名称： worker = ProductionWorker(employeeName, employeeShift, payRate) ）。

4. 在ProductionWorker.__init__声明的下面，我添加了以下行以为ProductionWorker提供name属性： self.name = name 。

Answer 2

除了@iCodez指出的错误外，您还没有定义self.__shift是什么，因此get_shift()在调用它时会引发错误。

您还没有定义self.__pay是什么，因此get_pay()将抛出NameError 。

我假设您是说这些方法分别返回self.__shift_number和self.pay_rate 。

哈哈，实际上，现在让我看得更近了，您对这些方法进行了双重定义 ，因此您立即用更正确的代码覆盖了错误的代码。 建议您删除错误代码。

Answer 3

您应该在get_shift函数中使用'=='而不是'='。

• =是赋值运算符

• ==是比较运算符

更正的代码：

---

def get_shift(self):
    if self.__shift_number == '1':
        s = 'Day shift'
    elif self.__shift_number == '2':
        s = 'Night shift'
    return s 

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