jar tvf xxx.jar
vim xxx.jar （其实 底层调用 unzip , zip 命令)配置一下 notepad++ F5
cmd /k D:"Program Files (x86)"\python\python.exe "$(FULL_CURRENT_PATH)" &pause &exit# 查看已经连接过的 wifi 密码for /f "skip=9 tokens=1,2 delims=:" %i in ('netsh wlan show profiles') do @echo %j | findstr -i -v echo | netsh wlan show profiles %j key=clear 进入 venv 生成 requirements.txtpip freeze > requirements.txt
pip install -r requirements.txt
关键字： DAG 有向无环图 ， 最左原则 实现 MRO (method resolution order) 方法解析顺序 之继承链
java 说我还是不太相信你，还是给你定一个规范吧， python 说 你是个成年人了，你知道为你的代码负责
不要对实例属性和类属性使用相同的名字，否则将产生难以发现的错误。实力属性总是会覆盖 类属型getattr()、setattr()以及hasattr() ,dir() 内省map filter 为 iter惰性计算的 Iterator, reduce 跟sorted 却是 立即计算模块搜索路径当我们试图加载一个模块时，Python会在指定的路径下搜索对应的.py文件，如果找不到，就会报错：try:#python2 from UserDict import UserDict #建议按照python3的名字进行import from UserDict import DictMixin as MutableMappingexcept ImportError:#python3 from collections import UserDict from collections import MutableMapping>>> import mymoduleTraceback (most recent call last): File "", line 1, in ImportError: No module named mymodule默认情况下，Python解释器会搜索当前目录、所有已安装的内置模块和第三方模块，搜索路径存放在sys模块的path变量中：>>> import sys>>> sys.path['', '/Library/Frameworks/Python.framework/Versions/3.6/lib/python36.zip', '/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6', ..., '/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages']如果我们要添加自己的搜索目录，有两种方法：一是直接修改sys.path，添加要搜索的目录：>>> import sys>>> sys.path.append('/Users/michael/my_py_scripts')这种方法是在运行时修改，运行结束后失效。第二种方法是设置环境变量PYTHONPATH，该环境变量的内容会被自动添加到模块搜索路径中。设置方式与设置Path环境变量类似。注意只需要添加你自己的搜索路径，Python自己本身的搜索路径不受影响。set和dict的唯一区别仅在于没有存储对应的value，但是，set的原理和dict一样，所以，同样不可以放入可变对象，因为无法判断两个可变对象是否相等，也就无法保证set内部“不会有重复元素”。请务必注意，dict内部存放的顺序和key放入的顺序是没有关系的。和list比较，dict有以下几个特点：查找和插入的速度极快，不会随着key的增加而变慢；需要占用大量的内存，内存浪费多。而list相反：查找和插入的时间随着元素的增加而增加；占用空间小，浪费内存很少。所以，dict是用空间来换取时间的一种方法。dict可以用在需要高速查找的很多地方，在Python代码中几乎无处不在，正确使用dict非常重要，需要牢记的第一条就是dict的key必须是不可变对象。这是因为dict根据key来计算value的存储位置，如果每次计算相同的key得出的结果不同，那dict内部就完全混乱了。这个通过key计算位置的算法称为哈希算法（Hash）。要保证hash的正确性，作为key的对象就不能变。在Python中，字符串、整数等都是不可变的，因此，可以放心地作为key。而list是可变的，就不能作为key：>>> key = [1, 2, 3]>>> d[key] = 'a list'Traceback (most recent call last): File " ", line 1, in TypeError: unhashable type: 'list'l = [4,5,6]t = (1,)s = {1}# s = set([1,2,3])d = {'name':'frank'}help(abs)把函数作为参数传入，这样的函数称为高阶函数，函数式编程就是指这种高度抽象的编程范式。from functools import reduceimport reexp = '99 + 88 + 7.6 ='reduce(lambda x,y:float(x)+float(y), filter(lambda x:True if x else False, map(lambda x:x.strip(), re.split(r'[\+=]',exp))))为什么要设计str、None这样的不变对象呢？因为不变对象一旦创建，对象内部的数据就不能修改，这样就减少了由于修改数据导致的错误。此外，由于对象不变，多任务环境下同时读取对象不需要加锁，同时读一点问题都没有。我们在编写程序时，如果可以设计一个不变对象，那就尽量设计成不变对象。凡是可作用于for循环的对象都是Iterable类型；凡是可作用于next()函数的对象都是Iterator类型，它们表示一个惰性计算的序列；集合数据类型如list、dict、str等是Iterable但不是Iterator，不过可以通过iter()函数获得一个Iterator对象。Python的for循环本质上就是通过不断调用next()函数实现的，例如：for x in [1, 2, 3, 4, 5]: pass实际上完全等价于：# 首先获得Iterator对象:it = iter([1, 2, 3, 4, 5])# 循环:while True: try: # 获得下一个值: x = next(it) except StopIteration: # 遇到StopIteration就退出循环 break
"""练习小明身高1.75，体重80.5kg。请根据BMI公式（体重除以身高的平方）帮小明计算他的BMI指数，并根据BMI指数：低于18.5：过轻18.5-25：正常25-28：过重28-32：肥胖高于32：严重肥胖"""height = 1.75weight = 80.5def BMI(height,weight): bmi = (weight/height)**2 results = ("过轻","正常","过重","肥胖","严重肥胖") ret = results[-1] if bmi<18.5: ret = results[0] elif 18.5<=bmi<25: ret = results[1] elif 25<=bmi<28: ret = results[2] elif 28<=bmi<32: ret = results[3] else: pass return retBMI(height,weight) def myhex(num): hex_list = [] t_mt = ('A','B','C','D','E','F') while True: mod_, num = num %16, num//16 hex_list.append(t_mt[mod_-10]) if mod_>9 else hex_list.append(str(mod_)) if num== 0 : break hex_list.append('0x') hex_list.reverse() return ''.join(hex_list)myhex(25)def my_octonary(num): octonary_list = [] while True: mod_,num = num%8,num//8 octonary_list.append(str(mod_)) if num == 0: break octonary_list.append('0o') octonary_list.reverse() return ''.join(octonary_list) my_octonary(9)# 基本递归def fac(n): if n>1: return n*fac(n-1) elif n==1: return 1 else: raise ValueError('数值必须大于等于1')# 尾递归方式def fac_iter(num,product): if num==1: return product else: return fac_iter(num-1,num*product) # 循环实现def fac2(n): if n<1: raise ValueError('数值必须大于等于1') acc = 1 while n>=1: acc*=n n-=1 return accfac_iter(4,1) str2float
# -*- coding: utf-8 -*-from functools import reducedigital_dict = {'0':0,'1':1,'2':2,'3':3,'4':4,'5':5,'6':6,'7':7,'8':8,'9':9}def str2float(s): i,j = s.split('.') left = reduce(lambda x,y:x*10+y,map(lambda x:digital_dict.get(x),i)) right = reduce(lambda x,y:x/10+y,list(map(lambda x:digital_dict.get(x),j))[::-1])/10 return left+rightstr2float('123.456') 累乘
# -*- coding: utf-8 -*-from functools import reducedef prod(L): return reduce(lambda x,y:x*y,L)print('3 * 5 * 7 * 9 =', prod([3, 5, 7, 9]))if prod([3, 5, 7, 9]) == 945: print('测试成功!')else: print('测试失败!') 名字这个我改了测试
names = ['adam', 'LISA', 'barT']def normalize(names): return list(map(lambda name:str.upper(name[0])+str.lower(name[1:]),names))# normalize(names)# 测试:L1 = ['adam', 'LISA', 'barT']L2 = normalize(L1)print(L2)
str2int
digital_dict = {'0':0,'1':1,'2':2,'3':3,'4':4,'5':5,'6':6,'7':7,'8':8,'9':9}from functools import reducedef str2int(s): return reduce(lambda x,y:x*10+y,map(lambda x:digital_dict.get(x),s))str2int('13579')def _odd_iter(): n = 1 while True: n = n + 2 yield n def _not_divisible(n): return lambda x: x % n > 0def primes(): yield 2 it = _odd_iter() # 初始序列 while True: n = next(it) # 返回序列的第一个数 yield n it = filter(_not_divisible(n), it) # 构造新序列 # 打印1000以内的素数:for n in primes(): if n < 1000: print(n) else: breakdef _odd_iter3(): n = 3 while True: yield n n+=2 def _not_divisible_3(n): return lambda x:x%n>0def prime_iter3(): yield 2 it = _odd_iter() while True: base_num = next(it) yield base_num it = filter(lambda x,y=base_num:x%y>0,it) for i in prime_iter3(): if i>50: break else: print(i,end=',')# -*- coding: utf-8 -*-L = [('Bob', 75), ('Adam', 92), ('Bart', 66), ('Lisa', 88)]def by_score(x): return x[1]def by_name(x): return x[0]sorted(L,key=by_score,reverse=True)sorted(L,key=by_name,reverse=True)def createCounter(): count = 0 def counter(): nonlocal count count += 1 return count return counterdef createCounter(): def f(): n=1 while True: yield n n +=1 g=f() def counter(): return next(g) return counter# 测试:counterA = createCounter()print(counterA(), counterA(), counterA(), counterA(), counterA()) # 1 2 3 4 5counterB = createCounter()if [counterB(), counterB(), counterB(), counterB()] == [1, 2, 3, 4]: print('测试通过!')else: print('测试失败!')def createCounter(): x = 0 def counter(): nonlocal x x += 1 return x return counterfrom collections import CounterCounter(s=3, c=2, e=1, u=1)Counter({'s': 3, 'c': 2, 'u': 1, 'e': 1})some_data=('c', '2', 2, 3, 5, 'c', 'd', 4, 5, 'd', 'd')Counter(some_data).most_common(2)[('d', 3), ('c', 2)]some_data=['c', '2', 2, 3, 5, 'c', 'd', 4, 5, 'd', 'd']Counter(some_data).most_common(2)[('d', 3), ('c', 2)]some_data={'c', '2', 2, 3, 5, 'c', 'd', 4, 5, 'd', 'd'}Counter(some_data).most_common(2)[('c', 1), (3, 1)] class Fib(): # 构造方法 def __init__(self,a=0,b=1): self.__a,self.__b = a,b def __enter__(self): print('Begin') # 这里 实际可以新增 打开资源动作 return self def __exit__(self,exc_type,exc_value,traceback): if exc_type: print('Error') else: print('End') #生成器 1 def __iter__(self): return self # 生成器 2 def __next__(self): self.__a, self.__b = self.__b, self.__a + self.__b if self.__a >10: raise StopIteration() return self.__a def __generatorfib(self,start,stop): x, y = 1,1 print(start,'-->',stop) begin = int(start) end = int(stop) while begin<=end: yield x x, y = y,x+y begin, end = begin+1,end-1 # 做成可下标取 def __getitem__(self,n): if isinstance(n,int): x, y = 1,1 for i in range(n): x, y = y,x+y return x # 下面这个没有真正支持 step if isinstance(n,slice): start = n.start if n.start else 0 stop = n.stop step = n.step x,y = 1,1 L = [] for n in range(0,stop,step): if n>=start: L.append(x) x, y = y,x+y return L[start:stop:step] # if isinstance(n,slice):# start = slice.start# stop = slice.stop# step = slice.step# inner_fib = self.__generatorfib(start,stop)# L = list(inner_fib)# return L[start,stop,step] def __getattr__(self,attr): if attr=='age': return lambda :18 raise AttributeError('\'Fib\' object has no attribute \'{}\''.format(attr)) # 打印给 user 看 def __str__(self): return 'Fib({},{})'.format(self.__a,self.__b) # 打印给程序员看 def __repr__(self): return self.__str__() # 重复声明一次是多余的但是指出这种用法 __repr__ = __str__ for n in eval('Fib(0,1)'): print(n,end=',') with Fib() as f: f[0:5:1] f.age() f.score() 元类 暂时学到这儿 ，产生 class 对象的 模板 必须继承自 type , 先有类来后有天，元类更在类之前, python 的 动态特性简直如此憨直 动到极致
class Field(object): def __init__(self,name,column_type): self.name = name self.column_type = column_type def __str__(self): return 'Field({name},{column_type})'.format(name=self.name,column_type=self.column_type) __repr__ = __str__ class IntegerField(Field): def __init__(self,name): super(IntegerField,self).__init__(name,'bigint') class VarcharField(Field): def __init__(self,name): super(VarcharField,self).__init__(name,'varchar(256)') class ModelMetaclass_frank(type): def __new__(cls,name,bases,attrs): if name=='Model': return type.__new__(cls,name,bases,attrs) print('found sub-model: {sub_model}'.format(sub_model=name)) #准备一个 object 属性 与 列关系映射 mappings = {} # 遍历 类属性仅 将 instance 为 Field 的 添加到 mappings 里保存起来 for attr_key,attr_value in attrs.items(): # attr_value ==》 if isinstance(attr_value,Field): print('Found mapping: {}==>{}'.format(attr_key,attr_value)) mappings[attr_key] = attr_value # 去除掉 attr (类属性) 中 有的，但是 mappings(可以看作是 实例属性 这里有点绕 这里的 实例是 type 创建出来的 class 实例) 中也有的 属性 ，避免 属性覆盖 for instance_key in mappings.keys(): attrs.pop(instance_key) # 将保存好的 实例属性 以及 table 名字 保留到 attr 中 attrs['__mappings__'] = mappings attrs['__table__'] = str.lower(name) # 这里的 那么 完全可以改为 xxx_+ name 比如 订单 register_user ,login_user return type.__new__(cls,name,bases,attrs) class Model(dict,metaclass=ModelMetaclass_frank): def __init__(self,*args,**kw): super(Model, self).__init__(*args,**kw) def __getattr__(self,key): try: value = self.get(key) except KeyError as e: raise AttributeError(r'"Model" object has no attribute "{}"'.format(key)) return value# def __setattr__(self,key,value):# self[key] = value def save(self): fields = [] params = [] args = [] for instance_attr_key,instance_attr_value in self.__mappings__.items(): fields.append(instance_attr_value.name) # 这里是 Field 类中的 self.name params.append('?')# print('-->',getattr(self,instance_attr_key,None))# args.append(getattr(self,instance_attr_key,None)) args.append(self.__getattr__(instance_attr_key)) print('fiels: --> ',','.join(fields)) print('params: -->',','.join(params)) print('args: -->',args) args = list(map(lambda s: '\''+s+'\'' if isinstance(s,str) else str(s),args)) sql = 'insert into {table_name}({fields_str}) values({values})'.format(table_name=self.__table__,fields_str=','.join(fields),values=','.join(args)) print(sql) class User(Model): # 定义类的属性到列的映射： id = IntegerField('id') name = VarcharField('username') email = VarcharField('email') password = VarcharField('password')# 创建一个实例：u = User(id=12345, name='Michael', email='test@orm.org', password='my-pwd')u.save() class Field(object): def __init__(self,name,column_type): self.name = name self.column_type = column_type def __str__(self): return ''.format(name=self.name,column_type=self.column_type) class IntegerField(Field): def __init__(self,name): super(IntegerField,self).__init__(name,'bigint') class StringField(Field): def __init__(self,name): return super(StringField,self).__init__(name,'varchar(256)') # 元类必须继承自 typeclass ModelMetaclass(type): def __init__(self,*args,**kw): return super(ModelMetaclass,self).__init__(*args,**kw) def __new__(cls,name,bases,attrs): print(cls,'<-->',name) if name=='Model': return type.__new__(cls,name,bases,attrs) print('Founding sub-model {sub_model}'.format(sub_model=name)) mappings = {} for k,v in attrs.items(): if isinstance(v,Field): mappings[k] = v for k in mappings.keys(): attrs.pop(k) attrs['__mappings__'] = mappings attrs['__table__'] = attrs.get('__table__',str.lower(name)) return type.__new__(cls,name,bases,attrs) class Model(dict,metaclass=ModelMetaclass): def __init__(self,*args,**kw): super(Model,self).__init__(*args,**kw) def __getattr__(self,key): try: value = self.get(key) except KeyError: raise('\'{object}\' has no attr \'{attr}\''.format(object=self.__name__,attr=key)) return value def save(self): fields = [] args = [] for k,v in self.__mappings__.items(): fields.append(v.name) args.append(self.__getattr__(k)) field_list = ','.join(fields) arg_list = ','.join(list(map(lambda x: '\'{}\''.format(x) if isinstance(x,str) else str(x),args))) sql = 'insert into {table_name}({field_list}) values({arg_list})'.format(table_name=self.__table__,field_list=field_list,arg_list=arg_list) print(sql) class LoginUser(Model): id = IntegerField('id') name = StringField('name') email = StringField('email') password = StringField('password') __table__ = 'loginuser' class RegisterUser(Model): id = IntegerField('id') name = StringField('name') email = StringField('email') password = StringField('password') __table__ = 'registeruser' login_user = LoginUser(id=1,name='Frank',email='frank@whatever.com',password='passwordxxx')login_user.save() register_user = RegisterUser(id=1,name='Frank',email='frank@whatever.com',password='passwordxxx')register_user.save() 内建模块
# datetimefrom datetime import datetime,timedeltanow = datetime.now()# datetime 转 timestampnow_timestamp = now.timestamp()# timestampe 转本地 datetimedt_local = datetime.fromtimestamp(now_timestamp)# timestampe 转utc datetimedt_utc = datetime.utcfromtimestamp(now_timestamp)# 时间戳 没有时区， datetime中携带print(dt_local.timestamp(),'<-->',dt_utc.timestamp())print('{}\n{}\n{}\n{}'.format(now,now_timestamp,dt_local,dt_utc))# 获取指定 日期和时间year = 2019month =3day =3hour = 15minute = 7dt_specified = datetime(year,month,day,hour,minute)print(dt_specified)# str 转 datetime str parsedatetime_str = '2019-03-03 15:22:00'datetime_parse_format = '%Y-%m-%d %H:%M:%S'cday = datetime.strptime(datetime_str,datetime_parse_format)print(cday)# datetime 转 str str formatprint(cday.strftime('%Y/%m/%d'))# 日期变化（delta） 用 timedeltanow = datetime.now()now_next3_hours = now+timedelta(hours=3)now_previous3_days = now+timedelta(days=-3)print('next 3 hours: {}'.format(now_next3_hours))print('now_previous3_days: {}'.format(now_previous3_days))from datetime import timezonetz_utc_8 = timezone(timedelta(hours=8))now = datetime.now()# 一开始 now 时区信息为 Noneprint(now.tzinfo)# 暴力设置一个时区now.replace(tzinfo=tz_utc_8)print(now)utc_now = datetime.utcnow()# 一开始这玩意儿压根木有时区信息啊print(utc_now.tzinfo)# 暴力设置时区信息utc_now = utc_now.replace(tzinfo=timezone.utc)#北京日期时间 东八区bj_dt = utc_now.astimezone(timezone(timedelta(hours=8)))# 西八区pst_dt = utc_now.astimezone(timezone(timedelta(hours=-8)))# 东 9 区tokyo_dt = utc_now.astimezone(timezone(timedelta(hours=9)))print('bj_dt: ',bj_dt)print('pst_dt: ',pst_dt)print('tokyo_dt: ',tokyo_dt)from datetime import datetime, timezone,timedeltaimport redef to_timestamp(dt_str,tz_str): re_dt_str_1 = r'\d{4}-\d{1,2}-\d{1,2}\s\d{1,2}:\d{1,2}:\d{1,2}' re_tz_str = r'^UTC([+-])(\d{1,2}):\d{2}$' tz_grps = re.match(re_tz_str,tz_str).groups() sign = tz_grps[0] hours = int(tz_grps[1]) if re.match(re_dt_str_1,dt_str): dt = datetime.strptime(dt_str,'%Y-%m-%d %H:%M:%S') if sign=='+': tz_info_x = timezone(timedelta(hours=hours)) else: tz_info_x = timezone(timedelta(hours=-hours)) dt = dt.replace(tzinfo=tz_info_x) else: print('re is wrong!') return dt.timestamp()# 测试:t1 = to_timestamp('2015-6-1 08:10:30', 'UTC+7:00')assert t1 == 1433121030.0, t1t2 = to_timestamp('2015-5-31 16:10:30', 'UTC-09:00')assert t2 == 1433121030.0, t2print('ok') collections 模块
def chunks(l, n): return [l[i:i+n] for i in range(0, len(l), n)]chunks(s,2)from collections import Iterator, Iterablefrom collections import defaultdictfrom collections import Counter, ChainMap, OrderedDict, namedtuple, dequefrom itertools import islice # 替代 切片，但是只能 是正数from itertools import zip_longest # 替代 zip 可以 对不一样个数的 进行迭代from concurrent.futures import ThreadPoolExecutor as Poolfrom collections import namedtuple, deque, defaultdict, OrderedDict, ChainMap, CounterPoint = namedtuple('Poing',['x','y','z'])p = Point(1,2,3)print(p.x,'--',p.y,'--',p.z)# 双向列表dq = deque([1,2,3,4])dq.append(5)dq.appendleft('a')dq.popleft()default_dict = defaultdict(lambda:'N/A') # 多了一个默认值default_dict['name']='frank'default_dict['age']od = OrderedDict([('b',1),('a',2),('c',3)]) # 按照插入的顺序有序od.get('a')# 可以实现一个FIFO（先进先出）的dict，当容量超出限制时，先删除最早添加的Keyfrom collections import OrderedDictclass LastUpdatedOrderedDict(OrderedDict): def __init__(self, capacity): super(LastUpdatedOrderedDict, self).__init__() self._capacity = capacity def __setitem__(self, key, value): containsKey = 1 if key in self else 0 if len(self) - containsKey >= self._capacity: last = self.popitem(last=False) print('remove:', last) if containsKey: del self[key] print('set:', (key, value)) else: print('add:', (key, value)) OrderedDict.__setitem__(self, key, value)# 应用场景 设置参数优先级from collections import ChainMapimport os, argparse# 构造缺省参数:defaults = { 'color': 'red', 'user': 'guest'}# 构造命令行参数:parser = argparse.ArgumentParser()parser.add_argument('-u', '--user')parser.add_argument('-c', '--color')namespace = parser.parse_args()command_line_args = { k: v for k, v in vars(namespace).items() if v }# 组合成ChainMap:combined = ChainMap(command_line_args, os.environ, defaults)# 打印参数:print('color=%s' % combined['color'])print('user=%s' % combined['user'])c = Counter()for ch in 'programing': c[ch] +=1print(c)c = dict()for ch in 'programing': if ch in c: c[ch] +=1 else: c[ch] = 1给单词按首字母分组方法一:words = ['apple','bat','bar','atom','book'] by_letter_grp_dict = {}for word in words: letter = word[0] if letter in by_letter_grp_dict: by_letter_grp_dict[letter].append(word) else: by_letter_grp_dict[letter] = [word]print(by_letter_grp_dict)方法二:内置的collections模块有一个叫做defaultdict的类，它可以使该过程更简单。传入一个类型或函数（用于生成字典各插槽所使用的默认值）即可创建一个defaultdict：words = ['apple','bat','bar','atom','book'] from collections import defaultdict by_letter = defaultdict(list) for word in words: by_letter[word[0]].append(word) print by_letter #defaultdict( , {'a': ['apple', 'atom'], 'b': ['bat', 'bar', 'book']}) 计数使用collections 库的 Counter>>> from collections import Counter>>> c = Counter('hello world!')>>> cCounter({'l': 3, 'o': 2, 'h': 1, 'e': 1, ' ': 1, 'w': 1, 'r': 1, 'd': 1, '!': 1})>>> c.most_common(1)[('l', 3)]>>> c.most_common(3)[('l', 3), ('o', 2), ('h', 1)]>>>>>> import collections>>> Card = collections.namedtuple('Card',['rank','suit'])>>> class French_Deck(object):... rank = [ str(i) for i in range(2,11,1)] + list('JQKA')... suit = 'Spade,Club,Heart,Diamond'.split(',')... def __init__(self):... self._cards = [Card(r,s) for s in suit for r in rank]... def __getitem__(self,position):... return self._cards[position]... def __len__(self):... return len(self._cards)...>>> cards = French_Deck()>>> len(cards)56from collections import namedtuplestock_list = [['AAPL','10.30','11.90'],['YAHO','9.23','8.19'],['SINA','22.80','25.80']]stock_info = namedtuple('stock_info',['name','start','end'])[stock_info(name,start,end) for name,start,end in stock_list ]stock_list# 与 update 不一样哦。。。from collections import ChainMapdict_1 = {'name':'Frank','age':18}dict_2 = {'name':'','age':20}dict_coalesce = ChainMap(dict_1,dict_2)dict_coalesce['name'] itertools 模块
from itertools import count, cycle, repeat, takewhile , chain, groupbyfor i in count(1): if i<=10: print(i,end=',') else: breakprint('\n'+'*'*100+'\n')nums = takewhile(lambda n:n<=10,count(1))print(list(nums))for nl in repeat('\n',3): print(nl)c = 0for ch in cycle('ABC'): if c>=10: break else: print(ch,end=',') c+=1print('\n'+'*'*100+'\n') for ch in chain('ABC','XYZ'): print(ch) for key,group in groupby('AAAaaabbBBBBBBBCCCccccddddEEEEDDD',lambda ch:ch.upper()): print(key,'--> ',list(group)) # -*- coding: utf-8 -*-import itertoolsfrom functools import reducedef pi(N): ' 计算pi的值 ' # step 1: 创建一个奇数序列: 1, 3, 5, 7, 9, ... odd_iter = itertools.count(1,2) # step 2: 取该序列的前N项: 1, 3, 5, 7, 9, ..., 2*N-1. odd_head = itertools.takewhile(lambda n:n<=2*N-1,odd_iter)# print(list(odd_head),end=',') # step 3: 添加正负符号并用4除: 4/1, -4/3, 4/5, -4/7, 4/9, ... odd_final = [4/n * ((-1)**i) for i,n in enumerate(odd_head)] # step 4: 求和: value = reduce(lambda x,y:x+y,odd_final) return value# 测试:print(pi(10))print(pi(100))print(pi(1000))print(pi(10000))assert 3.04 < pi(10) < 3.05assert 3.13 < pi(100) < 3.14assert 3.140 < pi(1000) < 3.141assert 3.1414 < pi(10000) < 3.1415print('ok') contextlib 模块
from contextlib import contextmanager,closing
xml.parsers.expat , lxml 等 模块
import lxmlfrom xml.parsers.expat import ParserCreateclass DefaultSaxHandler(object): def start_element(self, name, attrs): print('sax:start_element: %s, attrs: %s' % (name, str(attrs))) def end_element(self, name): print('sax:end_element: %s' % name) def char_data(self, text): print('sax:char_data: %s' % text)xml = r''' '''handler = DefaultSaxHandler()parser = ParserCreate()parser.StartElementHandler = handler.start_elementparser.EndElementHandler = handler.end_elementparser.CharacterDataHandler = handler.char_dataparser.Parse(xml) html 解析模块 html
from html.parser import HTMLParserfrom html.entities import name2codepointclass MyHTMLParser(HTMLParser): def handle_starttag(self, tag, attrs): print('<%s>' % tag) def handle_endtag(self, tag): print(' ' % tag) def handle_startendtag(self, tag, attrs): print('<%s/>' % tag) def handle_data(self, data): print(data) def handle_comment(self, data): print(' ') def handle_entityref(self, name): print('&%s;' % name) def handle_charref(self, name): print('&#%s;' % name)parser = MyHTMLParser()parser.feed(''' Some html HTML tutorial...
END''') 第三方 字符编码检测模块 chardet
import chardetdata = '最新の主要ニュース'.encode('euc-jp')chardet.detect(data){'confidence': 0.99, 'encoding': 'EUC-JP', 'language': 'Japanese'} 其他第三方模块
青出于蓝的 requests >> urllibPillow(新) PIL(2.7 远古时代)psutils <== process and system utilities
将字典的值转成object 的属性，递归d = {'a': 1, 'b': {'c': 2}, 'd': ["hi", {'foo': "bar"}]}def my_dict2obj(args): class obj(object): def __init__(self,d): for key,value in d.items(): if not isinstance(value,(list,tuple)): setattr(self,key,obj(value) if isinstance(value,dict) else value) else: setattr(self,key,[obj(i) if isinstance(i,dict) else i for i in value]) return obj(args)x = my_dict2obj(d)print(x.d)扩展拆箱>>> a = [1,2,3,4,5,6]>>> b,*c,d,e = a>>> b1>>> c[2, 3, 4]>>> d5>>> e6给单词按首字母分组方法一:words = ['apple','bat','bar','atom','book'] by_letter_grp_dict = {}for word in words: letter = word[0] if letter in by_letter_grp_dict: by_letter_grp_dict[letter].append(word) else: by_letter_grp_dict[letter] = [word]print(by_letter_grp_dict)方法二:内置的collections模块有一个叫做defaultdict的类，它可以使该过程更简单。传入一个类型或函数（用于生成字典各插槽所使用的默认值）即可创建一个defaultdict：words = ['apple','bat','bar','atom','book'] from collections import defaultdict by_letter = defaultdict(list) for word in words: by_letter[word[0]].append(word) print by_letter #defaultdict( , {'a': ['apple', 'atom'], 'b': ['bat', 'bar', 'book']}) 计数使用collections 库的 Counter>>> from collections import Counter>>> c = Counter('hello world!')>>> cCounter({'l': 3, 'o': 2, 'h': 1, 'e': 1, ' ': 1, 'w': 1, 'r': 1, 'd': 1, '!': 1})>>> c.most_common(1)[('l', 3)]>>> c.most_common(3)[('l', 3), ('o', 2), ('h', 1)]>>> 我见青山多巍峨,料青山见我应如是
# -*- coding: utf-8 -*-__author__ = 'Frank Li'import socketserver = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)server.bind(('127.0.0.1',6666))clients = set()print('server bind 127.0.0.1:6666...')while 1: try: data,addr = server.recvfrom(1024) clients.add(addr) if not data or data.decode('utf-8')=='pong': continue print('%s:%s >>> %s' % (addr[0],addr[1],data.decode('utf-8'))) for usr in clients: if usr!=addr: server.sendto(('%s:%s >>> %s' % (addr[0],addr[1],data.decode('utf-8'))).encode('utf-8'),usr) except Exception as e: pass # -*- coding: utf-8 -*-__author__ = 'Frank Li'import socket,threading,osclient = socket.socket(socket.AF_INET,socket.SOCK_DGRAM)client.sendto(b'pong',('127.0.0.1',6666))def myinput(): while 1: try: msg = input('>>>') yield msg except Exception as e: os._exit(0)def getMsg(client): while 1: try: r = client.recv(1024) print('\n',r.decode('utf-8'),'\n>>>',end='') except Exception as e: passc = myinput()def sendMsg(msg): while 1: msg = next(c) client.sendto(msg.encode('utf-8'),('127.0.0.1',6666))threading.Thread(target=sendMsg,args=(client,)).start()threading.Thread(target=getMsg,args=(client,)).start() inspect
import inspectdef a(a, b=0, *c, d, e=1, **f): passaa = inspect.signature(a)print("inspect.signature(fn)是:%s" % aa)print("inspect.signature(fn)的类型：%s" % (type(aa)))print("\n")bb = aa.parametersprint("signature.paramerters属性是:%s" % bb)print("ignature.paramerters属性的类型是%s" % type(bb))print("\n")for cc, dd in bb.items(): print("mappingproxy.items()返回的两个值分别是：%s和%s" % (cc, dd)) print("mappingproxy.items()返回的两个值的类型分别是：%s和%s" % (type(cc), type(dd))) print("\n") ee = dd.kind print("Parameter.kind属性是:%s" % ee) print("Parameter.kind属性的类型是:%s" % type(ee)) print("\n") gg = dd.default print("Parameter.default的值是: %s" % gg) print("Parameter.default的属性是: %s" % type(gg)) print("\n")ff = inspect.Parameter.KEYWORD_ONLYprint("inspect.Parameter.KEYWORD_ONLY的值是:%s" % ff)print("inspect.Parameter.KEYWORD_ONLY的类型是:%s" % type(ff)) import inspectdef func_a(arg_a, *args, arg_b='hello', **kwargs): print(arg_a, arg_b, args, kwargs)if __name__ == '__main__': # 获取函数签名 func_signature = inspect.signature(func_a) func_args = [] # 获取函数所有参数 for k, v in func_signature.parameters.items(): # 获取函数参数后，需要判断参数类型 # 当kind为 POSITIONAL_OR_KEYWORD，说明在这个参数之前没有任何类似*args的参数，那这个函数可以通过参数位置或者参数关键字进行调用 # 这两种参数要另外做判断 if str(v.kind) in ('POSITIONAL_OR_KEYWORD', 'KEYWORD_ONLY'): # 通过v.default可以获取到参数的默认值 # 如果参数没有默认值，则default的值为：class inspect_empty # 所以通过v.default的__name__ 来判断是不是_empty 如果是_empty代表没有默认值 # 同时，因为类本身是type类的实例，所以使用isinstance判断是不是type类的实例 if isinstance(v.default, type) and v.default.__name__ == '_empty': func_args.append({k: None}) else: func_args.append({k: v.default}) # 当kind为 VAR_POSITIONAL时，说明参数是类似*args elif str(v.kind) == 'VAR_POSITIONAL': args_list = [] func_args.append(args_list) # 当kind为 VAR_KEYWORD时，说明参数是类似**kwargs elif str(v.kind) == 'VAR_KEYWORD': args_dict = {} func_args.append(args_dict) print(func_args) 