Python笔记7#面向对象高级编程二

>>> class Student(object):
...     def __init__(self, name):
...         self.name = name
...
>>> stu1 = Student(‘jack‘)
>>> stu1
<__main__.Student object at 0x01740E70>
>>> print(stu1)
<__main__.Student object at 0x01740E70>

>>> class Student(object):
...     def __init__(self, name):
...         self.name = name
#print(stu1)调用__str__方法，返回用户看到的字符串
...     def __str__(self):
...         return ‘Student object (name: %s)‘ % self.name
...
>>> stu1 = Student(‘rose‘)
>>> stu1
<__main__.Student object at 0x0174A030>
>>> print(stu1)
Student object (name: rose)

>>> class Student(object):
...     def __init__(self, name):
...         self.name = name
...     def __str__(self):
...         return ‘Student object (name: %s)‘ % self.name
#stu1调用__repr__方法，返回开发者看到的字符串
...     __repr__ = __str__
...
>>> stu1 = Student(‘michael‘)
>>> stu1
Student object (name: michael)
>>> print(stu1)
Student object (name: michael)

#coding:utf-8

#创建一个fib数列迭代器
class Fib(object):
    def __init__(self):
        self.a, self.b = 0, 1
#实例本身就是迭代器，返回自身
    def __iter__(self):
        return self
#python3中next()方法改为__next__()
    def __next__(self):
        self.a, self.b = self.b, self.a + self.b
        if self.a > 500:
            raise StopIteration();
        return self.a
#__getitem__()可接收整数integer和切片slice
    def __getitem__(self, n):
        if isinstance(n, int):
            a, b = 1, 1
            for x in range(n):
                a, b = b, a + b
            return a
        if isinstance(n, slice):
            start = n.start
            stop = n.stop
            a, b = 1, 1
            L = []
            for x in range(stop):
                if x >= start:
                    L.append(a)
                a, b = b, a + b
            return L

for i in Fib():
    print(i)
print(‘-‘ * 50)
print(Fib()[5])
print(‘-‘ * 50)
print(Fib()[5:10])

1
1
2
3
5
8
13
21
34
55
89
144
233
377
--------------------------------------------------
8
--------------------------------------------------
[8, 13, 21, 34, 55]