Python类的未绑定错误

我到处都在研究，虽然我发现了相同的概念，但我似乎无法找到我错误的答案

我之前没有发布，因为我的帐户信息被遗忘在堆栈上，但我对这个初学者的错误感到非常失望

class Person(object):

    def __init__(self, name, phone):
        self.name = name
        self.phone = phone

class Employee(Person):

    total_salary = 0

    @staticmethod
    def total_salary(self, salary):
        return total_salary


    def __init__(self, name, phone, salary):
        self.name = name
        self.phone = phone
        self.salary = salary




class Student(Person):

    def __init__(self, name, phone, gpa):
        self.gpa = gpa
        self.name = name
        self.phone = phone

    def __str__(self):
        reply = ""
        reply = "Person " + self.name + " has phone " + self.phone + "\n" + " and is a Student with gpa " + str(self.gpa)
        return reply

class Professor(Employee):
    def __init__(self, name, phone, salary, clas_teach):
        self.clas_teach = clas_teach
        self.name = name
        self.phone = phone
        self.salary = salary

    def __str__(self):
        reply = ""
        reply = "Person " + self.name + " has phone " + self.phone + "\n" + " and is an Employee with salary " + str(self.salary) + "\n"
        reply += " and is a Professor assigned to class " + self.clas_teach
        return reply

class Staff(Employee):
    def __init__(self, name, phone, salary, position):
        self.position = position
        self.name = name
        self.phone = phone
        self.salary = salary
    def __str__(self):
        reply = ""
        reply = "Person " + self.name + " has phone " + self.phone + "\n" + " and is an Employee with salary " + str(self.salary) + "\n"
        reply += " and is Staff with title " + self.position
        return reply
# Create a list of people
People = [ Student("Sandy", "326-8324", 3.65), Student("Jordan", "632-7434", 3.1), \
           Professor("Leslie", "985-2363", 50000.00, "Info 501"),  \
           Staff("Alex", "743-4638", 25000.00, "Editor") ]

# display information about our people
print "These are the people in the university:"
for person in People:
   print person

# display the total salaries of all our employees and average GPA
#  of all of our students
print
print "Our total university payroll budget is: " + str(Employee.total_salary)
print "Our average student GPA is: " + str(Student.mean_gpa())

---

你的主要误解是课程如何运作。在代码中，您调用的是类而不是类的实例：

print "Our total university payroll budget is: " + str(Employee.total_salary)
print "Our average student GPA is: " + str(Student.mean_gpa())

这里的关键是：

Employee.total_salary

相反，你应该这样做：

leslie = Professor("Leslie", "985-2363", 50000.00, "Info 501")
print "Leslie's Salary: " + str(leslie.salary)

class Employee(Person):
    _total_salary = 0

    @classmethod
    def total_salary(cls):
        return cls._total_salary
...

print "Our total university payroll budget is: " + str(Employee.total_salary())

对于这种特定情况，您需要总工资，即所有员工工资的总和。你需要一批员工

def University():
    def __init__(self):
        self.employees[]

    def add_employee(self, employee):
        self.employees.append(employee)

    def get_total_payroll(self):
        total = 0
        for employee in self.employees:
            total += employee.salary
        return total

然后使用该类的实例：

university = University()
university.add_employee(Professor("Leslie", "985-2363", 50000.00, "Info 501"))
university.add_employee(Staff("Alex", "743-4638", 25000.00, "Editor"))

print "Total payroll: " + str(university.get_total_payroll())

---

显然，您需要做更多的调整，如员工和学生之间的排序等。但希望这足以让您开始。

您的总体设计存在问题，这些问题已在其他答案中介绍过，因此我将尝试解释当前代码不起作用的原因：

您已经创建了一个名为

total\u salary

的类属性，然后使用相同名称的方法对其进行阴影处理

当需要使用类方法时，您使用的是静态方法

您需要调用

total\u salary

作为一个方法，以返回其值

这些问题可以这样解决：

leslie = Professor("Leslie", "985-2363", 50000.00, "Info 501")
print "Leslie's Salary: " + str(leslie.salary)

class Employee(Person):
    _total_salary = 0

    @classmethod
    def total_salary(cls):
        return cls._total_salary
...

print "Our total university payroll budget is: " + str(Employee.total_salary())

---

但是请注意，代码仍然会引发一个

属性错误

，因为您试图调用尚未定义的

Student.mean\u gpa

。

您的类员工有一个同名的属性和方法。调用Employee.total_salary将返回该函数，因为在

MRO

中它将替换该属性

更改：

class Employee(Person):
    total_salary = 0

到

您在

Employee

中的

staticmethod total\u salary

返回的变量不存在（因为它只在方法范围内查看），您应该返回Employee.total\u salary\u值。像这样：

@staticmethod
def total_salary():
    return Employee.total_salary_value

在

员工

的

初始

中，您没有实例化您要继承的

人员

（与

学生

（继承

人员

）、

教授

和

员工

（两者都继承

员工

）中的情况相同

使用以下任一选项：

Person.__init__(self,name,phone)

或

仍然在init中，您没有将工资添加到

total\u salary\u值中

添加以下内容：

Employee.total_salary_value += self.salary

另外，在

Student

中不需要使用

self.name

和

self.phone

，因为

Person

已经具有此属性。（该属性和

Professor

和

Staff

中的其他变量相同）

最后，

Student

没有名为

mean\u gpa

的方法。你必须实现它

代码如下：

class Person(object):
    def __init__(self, name, phone):
        self.name = name
        self.phone = phone

class Employee(Person):
    total_salary_value = 0

    @classmethod
    def total_salary(cls):
        return cls.total_salary_value

    def __init__(self, name, phone, salary):
        Person.__init__(self,name,phone)
        self.salary = salary
        Employee.total_salary_value += self.salary

class Student(Person):
    all_gpa = []

    def __init__(self, name, phone, gpa):
        Person.__init__(self,name,phone)
        self.gpa = gpa
        Student.all_gpa.append(self.gpa)

    def __str__(self):
        return "Person {0} has phone {1} and is a Student with gpa {2}".format(self.name,self.phone,self.gpa)

    @classmethod
    def mean_gpa(cls):
        return sum(cls.all_gpa)/len(cls.all_gpa)


class Professor(Employee):
    def __init__(self, name, phone, salary, clas_teach):
        Employee.__init__(self,name,phone,salary)
        self.clas_teach = clas_teach

    def __str__(self):
        return "Person {0} has phone {1} and is an Employee with salary {2}\n" \
               "and is a Professor assigned to class {3}".format(self.name,self.phone,self.salary,self.clas_teach)


class Staff(Employee):
    def __init__(self, name, phone, salary, position):
        Employee.__init__(self, name, phone, salary)
        self.position = position

    def __str__(self):
        return "Person {0} has phone {1} and is an Employee with salary {2}\n" \
               "and is Staff with title {3}".format(self.name, self.phone, self.salary, self.position)

# Create a list of people
People = [ Student("Sandy", "326-8324", 3.65),
           Student("Jordan", "632-7434", 3.1),
           Professor("Leslie", "985-2363", 50000.00, "Info 501"),
           Staff("Alex", "743-4638", 25000.00, "Editor") ]

# display information about our people
print "These are the people in the university:"
for person in People:
   print person

# display the total salaries of all our employees and average GPA
#  of all of our students
print
print "Our total university payroll budget is: " + str(Employee.total_salary())
print "Our average student GPA is: " + str(Student.mean_gpa())

编辑：

正如@ekhumoro所说，最好使用@classmethod返回值

---

另外，您的

\uuuu str\uuuu

可以使用.format（）更清楚地显示出来

错误现在是，但是如果没有@staticmethod，它给了我你永远不会在total_salary方法中求和工资，你传递了两个没有使用的参数，

total_salary

是一个类属性，除了返回之外，它也没有被使用。你想做什么？你想如何解决这个问题？我正在尝试一个在People中添加员工的工资，但是还要确保如果我添加一个员工，它会添加工资。你不认为你需要另一个类吗，比如，

大学

，它有一个名为：

人

，这是一个人员列表的属性，然后你就有了

人员总预算

方法h遍历所有人员，如果他们是员工，则添加工资。

@staticmethod

和函数定义中的

self

很可能是错误的。