Python - 从出生日期获取员工年龄的类？

Question

import datetime
class Employee:
    def __init__ (self,first,last,pay,dob):
        self.first = first
        self.last = last
        self.pay = pay
        self.email = first + "." + last + "@company.com"
        self.dob = dob
    
    def fullname(self):
        return '{} {}'.format(self.first,self.last)
    
    def age(dob):
        today = date.today()
        return today.year - dob.year - ((today.month, today.day) < (dob.month, dob.day))
         
    
emp1 = Employee("aa","ss",122,date(1991,2,3))
emp2 = Employee("ww","ii",637,date(1997,8,24))
emp3 = Employee("ee","oo",986,date(1986,10,19))

#driver code
print(Employee.age(emp2))

我收到以下错误：

AttributeError: 'Employee' 对象没有属性 'year'

这有什么不正确的？

Answer 1

您的 Employee.age() 方法签名只有一个参数 - dob。当您调用它时，传递的第一个参数是实例。按照惯例，我们为此使用参数self。但是你使用dob。像其他方法一样坚持约定。然后使用self.dob.year

from datetime import date
class Employee:
    def __init__ (self,first,last,pay,dob):
        self.first = first
        self.last = last
        self.pay = pay
        self.email = first + "." + last + "@company.com"
        self.dob = dob
    
    @property
    def fullname(self):
        return '{} {}'.format(self.first, self.last) # in 3.6 return f'{self.first} {self.last}'
    
    def age(self):
        today = date.today()
        return today.year - self.dob.year - ((today.month, today.day) < (self.dob.month, self.dob.day))
         
    
emp1 = Employee("aa","ss",122,date(1991,2,3))
emp2 = Employee("ww","ii",637,date(1997,8,24))
emp3 = Employee("ee","oo",986,date(1986,10,19))

#driver code
print(emp1.age())

注意，我还添加了@property 装饰器，所以 fullname 是“只读”属性 并修复了导入

在 3.6+ 中，您可以使用 f 字符串。 age 和 e-mail property，如 fullname 可能是只读属性（即，您不应指定与 dob 矛盾的年龄），例如

@property
def age(self):
    today = date.today()
    return today.year - self.dob.year - ((today.month, today.day) < (self.dob.month, self.dob.day))

那你就可以这样使用了

print(emp1.age) # note the difference when it is method in the original class, and now when its property
     

Answer 2

您的employee 类没有年份属性

但是

employee.dob 有这个

import datetime
from datetime import date
class Employee:
    def __init__ (self,first,last,pay,dob):
        self.first = first
        self.last = last
        self.pay = pay
        self.email = first + "." + last + "@company.com"
        self.dob = dob
    
    def fullname(self):
        return '{} {}'.format(self.first,self.last)
    
    def age(dob):
        today = date.today()
        dob = dob.dob # get dob from the object(of employee class) <<<<< Single change
        return today.year - dob.year - ((today.month, today.day) < (dob.month, dob.day))
         
    
emp1 = Employee("aa","ss",122,date(1991,2,3))
emp2 = Employee("ww","ii",637,date(1997,8,24))
emp3 = Employee("ee","oo",986,date(1986,10,19))

#driver code
print(Employee.age(emp2))