strip() 方法用于移除字符串头尾指定的字符（默认为空格或换行符）或字符序列，返回的是一个字符串

len()方法返回对象长度或项目个数

len(s.strip()) > 0 的意思就是先去掉字符串s头尾的空格或者换行符，然后看此时返回的字符串的长度是多少。如果此时字符串的长度大于0，则改语句返回True，否则返回False

除了可以直接使用self.name = 'xxx'设置一个属性外，还可以通过 setattr(self, 'name', 'xxx') 设置属性。

张腾飞是个臭屌丝

高结函数 ，接收函数为参数，可返回函数

接收一个 函数，包装后，返回一个新的函数

class Fib(object):
    def __call__(self,n):
        s=[0,1]
        while len(s)<n:
            s.append(s[-1]+s[-2])
        return s
f = Fib()
print f(10)

class Student(object):

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

    @property
    def func1(self):
        return self.__score

    @func1.setter
    def funct2(self, x):
        if x< 0 or x > 100:
            raise ValueError('invalid score')
        self.__score = x
    @property
    def grade(self):
        if self.func1>=80:
            return "A"
        elif self.func1>=60:
            return "B"
        else:
            return "C"
        

s = Student('Bob', 59)
print s.grade

s.funct2= 60
print s.grade

s.funct2= 99

print s.grade

这样更好理解点，答案里面总是写相同的名字，针对新手来说反而更不容易理解，会联想相同名字的关联，实际没一点关系

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 "B"
        else:
            return "C"
        

s = Student('Bob', 59)
print s.grade

s.score = 60
print s.grade

s.score = 99
print s.grade

def gcd(a,b):
    if b==0:
        return a
    return gcd(b,a%b)
class Rational(object):
    def __init__(self, p, q):
        self.p = p
        self.q = q

    def __add__(self, r):
        return Rational(self.p * r.q + self.q * r.p, self.q * r.q)

    def __sub__(self, r):
        return Rational(self.p * r.q - self.q * r.p, self.q * r.q)

    def __mul__(self, r):
        return Rational(self.p * r.p ,self.q * r.q)

    def __div__(self, r):
        return Rational(self.p * r.q ,self.q * r.p)

    def __str__(self):
        g=gcd(self.p,self.q)
        return '{}/{}'.format(self.p/g,self.q/g)

    __repr__ = __str__

r1 = Rational(1, 2)
r2 = Rational(1, 4)
print r1 + r2
print r1 - r2
print r1 * r2
print r1 / r2

class Fib(object):

    def __init__(self, num):
        self.num=num
        self.s=[0,1]
        while len(self.s)<self.num:
            self.s.append(self.s[-1]+self.s[-2])
    def __str__(self):
        return str(self.s)
    __repr__=__str__
    def __len__(self):
        return len(self.s)
        

f = Fib(10)
print f
print len(f)

class Student(object):

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

    def __str__(self):
        return '(%s: %s)' % (self.name.lower(), 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.lower()<s.name.lower():
                return -1
            elif self.name.lower()>s.name.lower():
                return 1
                
L = [Student('Tim', 99), Student('Bob', 88), Student('Alice', 99)]
print sorted(L)

    def __cmp__(self, s):
        if self.score == s.score:
            return cmp(self.name, s.name)
        return -cmp(self.score, s.score)

class Person(object):

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

class Student(Person):

    def __init__(self, name, gender, score):
        super(Student, self).__init__(name, gender)
        self.score = score

    def __str__(self):
        return "(Student:{},{},{})".format(self.name,self.gender,self.score)
    __repr__=__str__

s = Student('Bob', 'male', 88)
print s

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

class Teacher(Person):

    def __init__(self, name, gender, course):
        Person.__init__(self,name,gender)
        self.course=course

t = Teacher('Alice', 'Female', 'English')
print t.name
print t.course

class Person(object):

    __count = 0
        
    def __init__(self,name):
        self.name=name
        Person.__count+=1
    @classmethod
    def how_many(cls):
        return cls.__count

print Person.how_many()

p1 = Person('Bob')

print Person.how_many()

#coding=utf-8
class Person(object):

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

    def get_grade(self):
        if self.__score>=90:
            return "A-优秀"
        elif self.__score>=60:
            return "B-及格"
        else:
            return "C-不及格"

p1 = Person('Bob', 90)
p2 = Person('Alice', 65)
p3 = Person('Tim', 48)

print p1.get_grade()
print p2.get_grade()
print p3.get_grade()

import functools

sorted_ignore_case = functools.partial(sorted,cmp=lambda s1,s2:cmp(s1.upper(),s2.upper()))

print sorted_ignore_case(['bob', 'about', 'Zoo', 'Credit'])