Python定制类

定制类

打印类信息

class Person(object):    def __init__(self, name, gender):        self.name = name        self.gender = genderclass Student(Person):    def __init__(self, name, gender, score):        super(Student, self).__init__(name, gender)        self.score = score    def __str__(self):        return '(Student: %s, %s, %s)' % (self.name, self.gender, self.score)    __repr__ = __str__s = Student('Bob', 'male', 88)print s

定义了 __str__  和 __repr__方法，定制自己的类对象的打印信息

定义类的比较函数

class Student(object):    def __init__(self, name, score):        self.name = name        self.score = score    def __str__(self):        return '(%s: %s)' % (self.name, self.score)    __repr__ = __str__    def __cmp__(self, s):        if self.score > s.score:            return -1        elif self.score < s.score:            return 1        else:            if self.name > s.name:                return 1            else:                return -1L = [Student('Tim', 99), Student('Bob', 88), Student('Alice', 99)]print sorted(L)

定义len函数

class Fib(object):        def __init__(self, num):        self.num = num        mylist = [0,1]        for i in range(1,num-1):            mylist.append(mylist[-1] + mylist[-2])        self.mylist = mylist        def __str__(self):        return '%s' %(self.mylist)    def __len__(self):        return len(self.mylist)        f = Fib(10)print fprint len(f)

@property

class Student(object):    def __init__(self, name, score):        self.name = name        self.__score = score    @property    def score(self):        return self.__score    @score.setter    def score(self, score):        if score < 0 or score > 100:            raise ValueError('invalid score')        self.__score = score    @property    def grade(self):        if self.score >= 80:            return 'A'        elif self.score < 60:            return 'C'        else:            return 'B's = Student('Bob', 59)print s.grades.score = 60print s.grades.score = 99print s.grade

限制类的属性

class Person(object):    __slots__ = ('name', 'gender')    def __init__(self, name, gender):        self.name = name        self.gender = genderclass Student(Person):    __slots__ = ('name','gender','score')    def __init__(self,name,gender,score):        super(Student,self).__init__(name,gender)        self.score = scores = Student('Bob', 'male', 59)s.name = 'Tim's.score = 99print s.score

__call__函数

class Fib(object):    def __call__(self,num):        mylist = [0,1]        for i in range(1,num-1):            mylist.append(mylist[-1] + mylist[-2])        return mylistf = Fib()print f(10)

一个类实例也可以成为一个可调用对象，需要实现__call__方法。