类学习笔记

class A(object):

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

    @staticmethod
    def talk():
        print(‘talk‘.center(50, ‘-‘))


A.talk()　　# 直接调用方法，不需要实例化

输出：-----------------------talk-----------------------

class Person(object):
    """
    自定义Person类
    """
    age = ‘22‘
    sex = ‘male‘

    def __init__(self, name):
        """构造方法"""
        self.name = name

    def __call__(self):
        """调用对象时执行"""
        print(‘My name is %s.‘ % self.name)

    def __getitem__(self, item):
        print(‘get item‘, item)

    def __setitem__(self, key, value):
        print(‘Set %s : [ %s ].‘ % (key, value))
        self.name = value

    def __delitem__(self, key):
        print(‘Delete %s.‘ % key)
        del key


person = Person(‘bloke‘)
person()    # 调用__call__方法
person[‘name‘] = ‘user01‘    # 调用__setitem__方法
person[‘name‘]    # 调用__getitem__方法
del(person[‘name‘])    # 调用__delitem__方法

# 输出：

    My name is bloke.
    Set name : [ user01 ].
    get item name
    Delete name.

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

    @property
    def info(self):
        return(‘Name: %s, Age: %s‘ % (self.name, self.age))

    @info.setter
    def info(self, name):
        self.name = name
        return(‘Name: %s, Age: %s.‘ % (self.name, self.age))

    @info.deleter
    def info(self):
        del self.age

person = Person(‘bloke‘, ‘22‘)  # 实例化
print(person.info)      # Name: bloke, Age: 22
person.info = ‘user01‘    #赋值
print(person.info)      # Name: user01, Age: 22
del person.info         # 删除age
print(person.info)      # 抛出异常，没有age属性

# 也可以使用:   info = property(get, set, del)   将类的get、set、del方法封装成info接口

    hasattr(obj, attr)      # 判断obj是否有attr属性
    getattr(obj, attr, default)      # 获取obj的attr属性，默认输出default
    delattr(obj, attr)      # 删除obj的attr属性
    setattr(obj, attr, value)     # 设置obj的attr属性的值为value