根本约定

ClsX: 类XValx: 变量xFuncx: 函数xCodex: 代码片段x

Python外部对象非凡办法/属性

1.__dict__属性：

ClsA.__dict__，类A的属性字典，包含属性，https://www.cnblogs.com/alvin2010/p/9102344.htmlValA.__dict__, 变量X的属性字典

2.__getattr__(self, item):

# 获取名为item的属性# 默认等同于：return self.__dict__[item]

3.__setattr__(self, item, value):

# 设置名为item的属性值为value# 默认等同于：self.__dict__[item] = value

迭代器和生成器

迭代是Python中遍历拜访汇合元素的一种形式。

迭代器是一个能够记住遍历的地位的对象。
迭代器对象从汇合的第一个元素开始拜访，直到所有的元素被拜访完完结。迭代器只能往前不会后退。
迭代器有两个根本的办法：iter() 和 next()。

https://www.runoob.com/python...

# 假如有个办法，能够依据传入的ID，从服务器获取内容，返回为空的时候阐明没有内容了def get_data(rid):    if rid > 5:        return     return '数据%s' % riddef get_data2(rid):    if rid > 3:        return    return 'Data%s' % rid# 当初咱们须要遍历全副数据i = 1while True:    data = get_data(i)    if not data:        break    print(data)    i += 1i = 1while True:    data = get_data2(i)    if not data:        break    print(data)    i += 1# 封装版本def get_all(func):    datas = []    i = 1    while True:        data = func(i)        if not data:            break        datas.append(data)        i += 1    return datasfor data in get_all(get_data):    print(data)# 生成器版本def gen_all(func):    i = 1    while True:        data = func(i)        if not data:            break        yield data        i += 1for data in gen_all(func=get_data):    print(data)# 迭代器版本class AllGetter:    def __init__(self, func):        self.func = func        self.i = 1        def __iter__(self):        return self     def __next__(self):        data = self.func(self.i)        if not data:            raise StopIteration        self.i += 1        return datax = (i for i in [1,2,3])while True:    print(x.__next__())    for data in AllGetter(func=get_data):    print(data)x = AllGetter(func=get_data)for data in x:    print(data)#等同于it = iter(x) # it = x.__iter__()while True:    print(next(it))

装璜器

# 如果咱们须要统计某些函数func1、func2的执行工夫import timedef func1():    time.sleep(1)def func2():    time.sleep(2)t1 = time.time()func1()print('func1', time.time() - t1)t2 = time.time()func2()print('func2', time.time() - t2)# 这类问题可形象为以下：# Code1# FuncX# Code2def func3(a, b):    print('a+b', a+b)# 定义函数的做法def timeit(func, *args, **kwargs):    t = time.time()    func(*args, **kwargs)    print(func.__name__, time.time() - t)timeit(func1)timeit(func2)timeit(func3, 1,2)def funcwrap(rawfunc):    def _wrap(newfunc):        newfunc.__name__ = rawfunc.__name__        return newfunc    return _wrap# 装璜器写法def timeit2(func):    from functools import wraps    def _func(*args, **kwargs):        t = time.time()        r = func(*args, **kwargs)        print(func.__name__, time.time() - t)        return r    return _func@timeit2def func4():    time.sleep(0.5)# 装璜器左右相似newfunc4 = timeit2(func4)func4 = newfunc4func4(1,2)# 装璜器用于类clzs = []def addit(clz):    clzs.append(clz)    return clz@additclass A(object):    pass@additclass B(object):    pass    @additclass C(object):    passprint(clzs)# 带参数的装璜器def asapi(logined):    def _wrap(func):        def _func(*args, **kwargs):            if logined:                print('err')                return             r = func(*args, **kwargs)            return r        return _func    return _wrap@asapi(logined=True)def fun6():    print('xxx')# 等同于logined = asapi(logined=True)@logineddef fun6():    print('xxx')

上下文管理器

# 某些状况下，咱们须要统计某段代码的执行工夫# 这类问题可形象为以下：# Code1# CodeX# Code2import timedef func1():    x = 2    # 咱们要统计上面这三行代码的执行工夫    a = 1    b = a + x    x = 4# 个别做法def func1():    x = 2    st = time.time()    a = 1    b = a + x    x = 4    print('cost time', time.time()-st)# 上下文治理做法class TimeIt(object):    def __enter__(self):        self.start = time.time()        def __exit__(self, exc_type, exc_val, exc_tb):        print('time cost', time.time()-self.start)def func1():    x = 2    with TimeIt():        a = 1        b = a + x        x = 4# 等同于def func1():    x = 2    ti = TimeIt()    ti.__enter__()    a = 1    b = a + x    x = 4    ti.__exit__(None,None,None)# 和上下文环境进行交互class TimeIt2(object):    def __enter__(self):        self.start = time.time()        self._marks = []        return self        def __exit__(self, exc_type, exc_val, exc_tb):        for n, t in self._marks:            print(n, t-self.start)            print('time cost', time.time()-self.start)        def mark(self, name):        print('->', name, time.time() - self.start)        self._marks.append((name, time.time()))with TimeIt2() as t:    time.sleep(2)    t.mark('T1')    time.sleep(1)    t.mark('T2')    time.sleep(0.5)# 等同于ti = TimeIt2()t = ti.__enter__()time.sleep(2)t.mark('T1')time.sleep(1)t.mark('T2')time.sleep(0.5)ti.__exit__(None,None,None)# 上下文交互2class SendContext(object):    def __init__(self, tag):        self.tag = tag        def __enter__(self):        self.msglist = []        return self.send        def __exit__(self, exc_type, exc_val, exc_tb):        print(self.msglist)        def send(self, userid):        self.msglist.append(userid)        with SendContext('order') as send:    for o in [1,2,3,4]:        send(1)