学习python第十天

今天学习了闭包，语法糖（列表推导式），装饰器，迭代器，生成器相关笔记如下

'''
知识点：
    1.闭包
    2.语法糖（列表推导式）
    3.装饰器
    4.迭代器
    5.生成器
'''

#高阶函数
# def func(a):
#     res=a()  #func2()
#     print(a())
#
# def func2():
#     return "python"
#
#
#
# func(func2())

#嵌套函数
# def func1():
#     def func2():
#         print("hello,world")
#     return func2()
#
# func1()

#闭包
def func1(a):
    def func2():
        print(a+a)
    return func2

#func1(2)()
#列表推导式
#三目运算暂时不讲

a=[]

for i in range(10):
    a.append(i)

#print(a)

b=[i for i in range(10)]  #列表推导式 用的地方很多
#print(b)

#不改变原有的调用方式，但是可以给函数添加新的功能
# def girl():
#     return "如此美丽"
#
# print(girl())

# def girl():
#     return "小明"+"如此美丽"

#print(girl())

# def modify(func):
#     result=func()
#     return "小明"+result

#print(modify(girl))
#装饰器（闭包做的）
def modify(func):
    def wrapper():
        print("开始验证")#当成代码逻辑
        result=func()
        return "小明"+result
    return wrapper


@modify
def girl():
    return "如此美丽"

print(girl())

#python 内置装饰器 3个
class Rectangles:
    def __init__(self,length,width):
        self.length=length
        self.width=width

    def area(self):
        areas=self.length*self.width
        return areas

    @property#像属性一样访问我们的方法，调用可以不用括号
    def areas(self):
        areas=self.length*self.width
        return areas

    @staticmethod #静态方法 和self进行解绑
    def func():
        print('HELLO,WORLD')

    @classmethod  #类方法  传递的就是类本身
    def show(cls):
        print("python")

a=Rectangles(10,5)
#print(a.area())
#print(a.areas)
#a.func()
#Rectangles.func()

#使用类来做装饰器
class TestClass:
    def __init__(self,func):
        self.func=func

    def __call__(self, *args, **kwargs):
        print("正在验证")
        return self.func

@TestClass
def func_test():
    print("qi")

func_test()

#带参数的装饰器

def func1(a):
    def func2(func):
        def func3(*args,**kwargs):
            return a+func(*args)
        return func3
    return func2

@func1("haha")
def qiyue(c):
    return "heihei"+c

print(qiyue("嗯嗯"))

#迭代器  优势是可以优化内存，惰性计算
from itertools import count

li=[1,2,3,4,5,6,]

#print(dir(li))
#__iter__ 代表是一个可迭代的对象
#__next__
'''
['__add__', '__class__', '__contains__', '__delattr__',
 '__delitem__', '__dir__', '__doc__', '__eq__',
 '__format__', '__ge__', '__getattribute__', '__getitem__', 
'__gt__', '__hash__', '__iadd__', '__imul__', '__init__', 
'__init_subclass__', '__iter__', '__le__', '__len__', 
'__lt__', '__mul__', '__ne__', '__new__', '__reduce__', 
'__reduce_ex__', '__repr__', '__reversed__', 
'__rmul__', '__setattr__', '__setitem__', 
'__sizeof__', '__str__', '__subclasshook__', 
'append', 'clear', 'copy', 'count', 'extend', 
'index', 'insert', 'pop', 'remove', 'reverse', 'sort']

'''#有__iter__没有__next__说明是一个可迭代对象
a=iter(li)
print(dir(a))
'''
['__class__', '__delattr__', '__dir__', '__doc__', 
'__eq__', '__format__', '__ge__', '__getattribute__', 
'__gt__', '__hash__', '__init__', '__init_subclass__',
 '__iter__', '__le__', '__length_hint__', '__lt__', 
 '__ne__', '__new__', '__next__', '__reduce__', 
 '__reduce_ex__', '__repr__', '__setattr__', '__setstate__',
 '__sizeof__', '__str__', '__subclasshook__']
'''#有了__next__说明是一个迭代器
print(next(a))
print(next(a))
print(next(a))
print(next(a))
print(next(a))
print(next(a))

# itr=iter(li)
# try:
#     while True:
#         a=next(itr)
#         print(a)                    #本质是一个for循环
# except StopAsyncIteration as e:
#     pass

#生成器

# def func():
#     yield 1
#     yield 2
#     yield 3
#     yield 4
#
# b=func()
# print(b.__next__())
# print(next(b))

def cycke(a,n):
    count = 0
    while True:
        if count<n:
            count +=1
            yield a
        else:
            break

haha = cycke("七月",8)

print(haha)
for i in haha:
    print(i)