ZhouYang1993

def fibonacci():
    x, y = 0, 1
    while True:
        x, y = y, x + y
        yield x


p = fibonacci()

ZhouYang1993

def fibonacci():
    x, y = 0, 1
    while True:
        x, y = y, x + y
        yield x

fib = fibonacci()

ZhouYang1993

def times_two(nums):
    for n in nums:
        yield n * 2


def natural_number(maximum):
    x = 0
    while x < maximum:
        yield x
        x += 1

ZhouYang1993

def times_two(nums):
    for n in nums:
        yield n * 2

def natural_number(maximum):
    x = 0
    while x < maximum:
        yield x
        x += 1

ZhouYang1993

class Student:
    def __new__(cls, *args, **kwargs):
        print("Running __new__() method.")
        instance = object.__new__(cls)
        return instance

    def __init__(self, first_name, last_name):
        print("Running __init__() method.")
        self.first_name = first_name
        self.last_name = last_name

ZhouYang1993

class Singleton_Student(object):
    _instance = None

    def __new__(cls, *args, **kwargs):
        print("Running __new__() method.")
        if not Singleton_Student._instance:
            Singleton_Student._instance = object.__new__(cls)
        return Singleton_Student._instance

    def __init__(self, first_name, last_name):

ZhouYang1993

class Student(object):

    def __new__(cls, *args, **kwargs):
        print("Running __new__() method.")
        return None

    def __init__(self, first_name, last_name):
        print("Running __init__() method.")
        self.first_name = first_name
        self.last_name = last_name

ZhouYang1993

class Student:
    def __init__(self):
        self._score = 0
        
Yang = Student()
print(Yang._score)
# 0
Yang._score = 100
del Yang._score

ZhouYang1993

class Student:
    def __init__(self):
        self._score = 0

    def set_score(self, s):
        if 0 <= s <= 100:
            self._score = s
        else:
            raise ValueError('The score must be between 0 ~ 100!')
Yang = Student()

ZhouYang1993

class Student:
    def __init__(self):
        self._score = 0

    def set_score(self, s):
        if 0 <= s <= 100:
            self._score = s
        else:
            raise ValueError('The score must be between 0 ~ 100!')
Yang = Student()