Python定制类，,1.__str__c

Python定制类，,1.__str__c

1.__str__

class Student(object):    def __init__(self, name):        self._name = namem = Student("michael")print m

<__main__.Student object at 0x0000000003280EF0>

为了使print类的结果格式更加方便阅读

重写__str__(self)

class Student(object):    def __init__(self, name):        self._name = name            def __str__(self):        return "Student Name is %s !"% self._namem = Student("michael")print m

Student Name is michael !

__repr__类似与__str__，不同的__repr__主要运用与开发者交互方面

2.__iter__

将类变为可迭代的类型

class Fib(object):    def __init__(self):        self.a = 0        self.b = 1    def __iter__(self):        return self    def next(self):        self.a, self.b = self.b, self.a + self.b        if self.a > 100:            raise StopIteration()        return self.afor n in Fib():    print n

3.__getitem__

用于迭代的时候，能用数组下标访问其中的变量

class Fib(object):    def __init__(self):        self.a = 0        self.b = 1    def __iter__(self):        return self    def next(self):        self.a, self.b = self.b, self.a + self.b        if self.a > 100:            raise StopIteration()        return self.a    def __getitem__(self, item):        for i in range(item):            self.a, self.b = self.b, self.a + self.b        return self.aprint Fib()[11]

4.__getattr__

直接上例子：

class Person(object):    def __init__(self):        self.name = "Michael"    def __getattr__(self, item):        if item == "age":            self.age = 22            return self.agem = Person()print m.__getattr__("age")

附上一个动态生成路径的代码

class Clain(object):    def __init__(self, path=""):        self._path = path    def __getattr__(self, item):        return Clain("%s/%s"%(self._path, item))    def __str__(self):        return self._pathprint Clain().usr.bin.env.python

/usr/bin/env/python

5.__call__

直接调用实例

上个例子：

class Person(object):    def __init__(self):        self.name = "Michael"    def __call__(self, *args, **kwargs):        print "My name is %s" % self.name        m = Person()m()

My name is Michael

附：__getattr__ 和 __call__ 联合调用

class Clain(object):    def __init__(self, path=""):        self._path = path    def __getattr__(self, item):        return Clain("%s/%s"%(self._path, item))    def __str__(self):        return self._path    def __call__(self, *args, **kwargs):        for i in args:            self._path = "%s/%s" % (self._path, i)        return Clain(self._path)print Clain().usr("Michael").bin.env.python

/usr/Michael/bin/env/python

Python定制类