def wrapper(func):def inner(*args,**kwargs):ret =func(*args,**kwargs)return retreturn inner

import  time

def wrapper(func):    def innner(*args,**kwargs):        start = time.time()        time.sleep(1)        func(*args,**kwargs)        end = time.time()        print(end-start)    return innner

@wrapper # func = wrapper(func)def func():    print('hello world')func()

# 给函数加上认证功能，登录一次就可以多次调用函数FLAG = False
def login(func):def innner(*args,**kwargs):global FLAGif FLAG: ret =func(*args,**kwargs) return func else: username = input('username: ') password = input('password: ') if username == 'wangys' and password == 'wangys': FLAG = True ret =func(*args,**kwargs) return func else:print("用户名密码错误") return innner @login def shoplist_add(): print('增加一个商品') @login def shoplist_delete(): print('删除一个商品') shoplist_add() shoplist_delete()

列表
l = [1,2,3,4]
for i in l:   print(i)  元祖
t = (1,2,3,4
for i  in t:print(i)字典
dic = {'name':'wangys','age':18}
for i in dic:                        print(i)                         字符串
name = 'wangys'
for i in name:     print(i)       

# dir方法可以将所有方法取到，我们可以通过下面的手段来查看是否有__iter__方法，也就是是否可以被for循环print('__iter__' in dir([]))
print('__iter__' in dir(''))
print('__iter__' in dir(()))
print('__iter__' in dir({})) 

# 列表通过__iter__方法，得到了一个迭代器对象print([].__iter__())
<list_iterator object at 0x000001CF7C9AD0B8>

# 查看迭代器相对于可迭代对象增加了哪些方法
print(dir([]))
print(dir([].__iter__()))
print(set(dir([].__iter__()))-set(dir([]))) {'__length_hint__', '__setstate__', '__next__'}__next__方法就可以将一个一个元素取出

# list是可迭代对象
# list_iterator，是通过list的__iter__方法获得的迭代器
# 通过迭代器的__next__方法，一个一个取出值
list = [1,2,3]
list_iterator = list.__iter__() print(list_iterator.__next__())
print(list_iterator.__next__())
print(list_iterator.__next__())
print(list_iterator.__next__())   # 因为有三个元素，所以这里会报错StopIteration

# 会报错
list = [1,2,3,4]
list_iterator=list.__iter__()
while True:                        item = list_iterator.__next__()print(item)                    StopIteration# 通过异常处理机制

list = [1,2,3,4]
list_iterator=list.__iter__()
while True:                            try:                               item = list_iterator.__next__()print(item)                    except   StopIteration:            break                          

def generator(): # 生成器函数print(1)yield 'a'ret = generator() # ret是一个生成器
print(ret)<generator object generator at 0x0000018492149830>

# 函数执行后，会得到一个生成器函数，该生成器既有__iter__和__next__方法

def generator(): # 定义一个生成器函数print(1)yield 'a'print(2)yield 'a'g = generator() # 得到一个生成器g
ret = g.__next__()
print(ret)
ret = g.__next__()
print(ret)
ret = g.__next__()
print(ret)

def generator():print(1)yield 'a'print(2)yield 'a'g = generator()
for i in g:print(i)

def generator(): # 定义一个生成器函数print('123')content = yield '**a'print('456')print(content)yield  '**b'g = generator() # 得到一个生成器
ret =g.__next__()  # 执行generator,到yield，并把返回值给ret
print(ret)  # 打印返回值
ret =g.send('haha') # 执行generator，并把'haha'赋值给content，并且执行到yield，返回值给ret
print(ret) # 打印ret

g1 = (i for i in range(100) if i%3 ==0)
print(g1)
print(list(g1))

g1 = (i**2 for i in range(100) if i%3==0)
print(list(g1))

names = [['Tom', 'Billy', 'Jefferson', 'Andrew', 'Wesley', 'Steven', 'Joe'],['Alice', 'Jill', 'Ana', 'Wendy', 'Jennifer', 'Sherry', 'Eva']]
# 常规做法
l1=[]
for line in names:for name in line:if name.count('e') ==2:l1.append(name)
print(l1)
# 列表推导式
l1=[name for line in names for name in line if name.count('e') ==2]
print(l1)
# 生成器表达式
g1 = (name for line in names for name in line if name.count('e')==2)
print(list(g1)

# 常规做法
l1=[]
for num in range(100):if num%2 ==0:l1.append(num)
print(l1)# 列表推导式
li = [num for num in range(100) if num%2 ==0]
print(li)

name = ['wangys','wc','huisz','cyf']
l1=[ i.upper() for i in name if len(i) >3]
print(l1)

l1 = [(i,j) for i in range(5) for j in range(5) if i%2==0 and j%2==1]
print(l1)

M = [[1,2,3],[4,5,6],[7,8,9]]
l1 = [ i[2] for i in M]
print(l1)

m = [3, 6, 9]
l1 = [[i-2,i-1,i] for i in  m]
print(l1)

l1 = [i**2 for i in range(50) if i%3 ==0]
print(l1)

x = {'name':'wangys','Values':[{'timestamp':1517991992.94,'values':100,},{'timestamp': 1517992000.94,'values': 200,},{'timestamp': 1517992014.94,'values': 300,},{'timestamp': 1517992744.94,'values': 350},{'timestamp': 1517992800.94,'values': 280}],}
l1 = [ (el['timestamp'],el['values']) for el in x['Values']]
print(l1)# [(1517991992.94, 100), (1517992000.94, 200), (1517992014.94, 300), (1517992744.94, 350), (1517992800.94, 280)]

lst1 = ['jay', 'jj', 'sylar']
lst2 = ['周杰伦', '林林俊杰', '邱彦涛']
dic = {lst1[k]:lst2[v] for k in range(len(lst1)) for v in range(len(lst2))}
print(dic)