Python之面向对象

1、面向对象基本概念

　　类、类变量、数据成员、方法重载、实例变量、继承、实例化、方法、对象。

2、创建一个类

 

#coding=UTF-8

class Employee:
    'The basic class of all the Employees.'
    empCount = 0 # 类变量，其值为类的所有实例共享，访问方式：Employee.emCount

    # 构造函数：初始化对象。名称__init__ 固定。
    def __init__(self, name, salary):
        self.name = name
        self.salary = salary
        Employee.empCount += 1

    def displayCount(self):
        print('Total employee is %d', Employee.empCount)

    def displayEmployee(self):
        print('Name:%s, Salary:%d.' % (self.name, self.salary))
    
    # 析构函数：当对象不再被使用时被调用
    def __del__(self):
        class_name = self.__class__.__name__
        print(class_name, 'destroyed')

# 实例化时，需和class对其，否则报NameError: name 'Employee' is not defined
    # emp1 = Employee('Gari', 2000)
emp1 = Employee('Tom', 2000)
emp2 = Employee('Good', 2000)

emp1.displayEmployee()
emp2.displayEmployee()

print("Total Employee %d" % Employee.empCount)

# 添加一个属性
emp1.age = 7
emp2.age = 8
print("emp1 is %d years old, and emp2 is %d." % (emp1.age, emp2.age))
del emp1.age
# 和java不一样，类的对象的属性可以删除
# print("emp1 is %d years old, and emp2 is %d." % (emp1.age, emp2.age))
hasAge = hasattr(emp1, 'age')
print('Does emp1 have age attr? ', hasAge)
emp1Name = getattr(emp1, 'name')
print('The name of emp1 is ', emp1Name)
setattr(emp2, 'salary', 20000)
print("emp2's salary is %d now." % emp2.salary)
delattr(emp2, 'salary')
hasSalary = hasattr(emp2, 'salary')
print('Does emp2 have salary attr? ', hasSalary)

# 内置类属性
print("Employee.__doc__:", Employee.__doc__)
print("Employee.__name__:", Employee.__name__)
print("Employee.__module__:", Employee.__module__)
print("Employee.__bases__:", Employee.__bases__)
print("Employee.__dict__:", Employee.__dict__)

emp2 = emp1
print(id(emp1), id(emp2))