# ************************************************************1
# sorted
# 对list、dict进行排序，有两个方法
# 1.用list成员函数sort进行排序，在本地进行排序，不返回副本，默认按升序排序
# 2.用built-in函数sorted进行排序（从2.4开始），返回副本，原始输入不变
# sorted(iterable, key=None, reverse=False)
# 参数说明：
# iterable：是可迭代类型;
# key：传入一个函数名，函数的参数是可迭代类型中的每一项，根据函数的返回值大小排序;
# reverse：排序规则. reverse = True 降序 或者 reverse = False 升序，有默认值。
# 返回值：有序列表
# 例一
# l1 = [1,2,3,-1,-2,-4,-6]
# l2 = sorted(l1,key=abs)
# print(l2)
# # 例二
# l = [[1,2],[3,4,5,6],(7,),'123']
# print(sorted(l,key=len))
# ************************************************************2
# repr：Return the canonical string representation of the object.
# For many object types, including most builtins, eval(repr(obj)) == obj.
# a = [1,2,3,4,5,[23,3,5,'sdgsdf']]
# b = repr(a) # b = '[1, 2, 3, 4, 5, [23, 3, 5, 'sdgsdf']]'
# c = eval(b) # c = [1, 2, 3, 4, 5, [23, 3, 5, 'sdgsdf']]
# print(type(a)) # <class 'list'>
# print(type(b)) # <class 'str'>
# print(type(c)) # <class 'list'>
# ************************************************************3
# round: 取小数位数，默认取0为小数，会自动四舍五入
# 被舍掉的第一位大于5时才会进1，round(0.50) == 0.
# print(round(0.9)) # 1：int
# print(round(1.9,1)) # 1.9
# print(round(1.944,2)) # 1.9
# print(round(0.50)) # 0
# ************************************************************4
# # sum(iterable[,start = 0])
# print(sum([1,2,3,4,5,6])) # 21: 默认start为0
# print(sum([1,2,3,4,5,6],10)) # 31 start = 10
# ************************************************************5
# min
# print(min(1,2,3,4,5,6))# 可以接收多个参数
# print(min([1,2,3,44,5,6,787]))# 也可以接收一个iterable
# print(min((23,4,5,6,76,676543)))
# print(min([[1,2,3],[12],[23,4213,45,3]],key=len)) # [12]
# ************************************************************6
# max
# print(max(1,2,3,4,5,6))# 可以接收多个参数
# print(max(1,2,-8,3,4,5,6,key=lambda x:x*x)) # -8
# print(max([1,2,3,44,5,6,787]))# 也可以接收一个iterable
# print(max((23,4,5,6,76,676543)))
# print(max([[1,2,3],[12],[23,4213,45,3]],key=len)) # [23, 4213, 45, 3]
# ************************************************************7
# filter: filter(function or None, iterable) --> filter object
# Return an iterator yielding those items of iterable for which function(item)
# is true. If function is None, return the items that are true.
# def is_odd(x):
# return x%2 ==1
# # print(is_odd(1))
# a = filter(is_odd,[1,2,3,4,6,7,34,63,23]) #
# print(type(a))
# for i in a:
# print(i)
# print(list(filter(lambda x:x%2==1,[1,2,3,4,6,7,32,453,23])))
# ************************************************************8
# map: map(func, *iterables) --> map object
# Make an iterator that computes the function using arguments from
# each of the iterables. Stops when the shortest iterable is exhausted.
# print(list(map(abs,[1,-3,2,3,-6,2.5]))) # [1, 3, 2, 3, 6, 2.5]
# print(list(map(lambda x,y:x+y,[1,2,3,4,5],[1,2,3,4,5]))) # [2, 4, 6, 8, 10]
# ************************************************************9
# abs 求绝对值
# print(abs(-5))
# ************************************************************10
# divmod : Return the tuple ((x-x%y)/y, x%y)
# print(divmod(7,2)) # (3, 1)
# # print(divmod(9,5)) # (1, 4)
# ************************************************************11
# pow: Equivalent to x**y (with two arguments) or x**y % z (with three arguments)
# print(pow(2,3)) # 2**3
# print(pow(3,4,2)) # (3**4)%2
# ************************************************************12+2
# ord： Return the Unicode code point for a one-character string.
# print(ord('1')) # 49
# print(ord('a')) # 97
# print(ord('中')) # 20013
# chr:
# print(chr(97)) # a
# print(chr(20013)) # 中
# ascii(o) # 返回一个对象的字符串表示，属于ascii的，原样表示，不属于ascii的，用'u'打标记
# print(ascii(' ')) # ' '
# print(ascii('wjlwr我爱你')) # 'wjlwru6211u7231u4f60'
# lst = [1,23,32,'asdkf我爱你''aslkdf']
# l2 = ascii(lst)
# print(l2,type(l2)) # [1, 23, 32, 'asdkfu6211u7231u4f60aslkdf'] <class 'str'>
# ************************************************************13
# format
# print(format(3.1415936))
# print(str(3.1415936))
# 字符串可以提供的参数,指定对齐方式，<是左对齐， >是右对齐，^是居中对齐
# print(format('test','<20'))
# print(format('test','>20'))
# print(format('test','^20'))
# 整形数值可以提供的参数有 'b' 'c' 'd' 'o' 'x' 'X' 'n' None
# print(format(3,'b')) # 转换成二进制
# print(format(97,'c')) # 转换成uinicode字符
# print(format(11,'d')) # 转换成十进制
# print(format(11,'o')) # 转换成八进制
# print(format(11,'x')) # 转换成16进制,字母用小写表示
# print(format(11,'X')) # 转换成16进制,字母用大写表示
# print(format(11,'n')) # 和d一样
# print(format(11)) # 默认和d一样
# #浮点数可以提供的参数有 'e' 'E' 'f' 'F' 'g' 'G' 'n' '%' None
# print(format(314149267,'e')) #科学计数法，默认保留6位小数
# print(format(314149267,'0.8e')) #科学计数法，指定保留8位小数
# print(format(314159267,'0.2E')) # 科学计数法，指定保留2位小数，采用大写E表示
# print(format(314159267,'f')) # 小数点表示法，默认保留6位小数
# print(format(3.14159267000,'f')) # 小数点表示法，默认保留6位小数
# print(format(3.14159267000,'0.8f')) # 小数点表示法，指定保留8位小数
# print(format(3.14159267000,'0.10f')) # 小数点表示法，指定保留10位小数
# print(format(3.14e+10000,'F')) # 小数点表示法，无穷大换成大写字母
#g的格式化比较特殊，假设p为格式中指定的保留小数位数，先尝试采用科学计数法格式化，得到幂指数exp，
# 如果-4<= exp <p，则采用小数计数法，并保留p-1-exp位小数，否则按小数计数法计数，并按p-1保留小数位数
# print(format(314156.9267,'0.3g')) # 3.14e+05
# print(format(3.141569267,'0.3g'))
# ************************************************************14
# zip: 返回一个可迭代的zip对象，如果迭代完后继续取数据，会产生StopIteration
# zip(iter1 [,iter2 [...]]) --> zip object
# l = [1,2,3,4]
# l2 = ['a','b','c']
# l3 = ['q','e']
# print(list(zip(l))) # [(1,), (2,), (3,), (4,)]
# print(list(zip(l,l2,l3))) # [(1, 'a', 'q'), (2, 'b', 'e')]
# ************************************************************15,16,17
# eval、exec和compile
# exec('print(123)')
# eval('print(123)')
# print(eval('1+2+3+4'))
# print(exec('1+2+3+4')) # None
# exec 和eval都可以执行字符串类型的代码
# eval有返回值 -- 有结果的简单计算
# exec没有返回值 -- 简单流程控制
# eval只能用在你明确知道你要执行的代码是什么
# code = '''for i in range(10):
# print(i*'*')'''
# exec(code)
# # eval(code) # SyntaxError: invalid syntax
# code1 = 'for i in range(0,10):print(i)'
# compile1 = compile(code1,'','exec')
# exec(compile1)
# eval(compile1) # 可以正确执行
# code2 = '1+2+3+4'
# compile2 = compile(code2,'','eval')
# print(eval(compile2))
# code3 = "name = input('please input your name:')"
# compile3 = compile(code3,'','single')
# exec(compile3)
# print(name)
# ************************************************************18
# all(iterable):判断iterable里面有没有bool值为False的元素，
# 有则返回False，如果参数为[],()等，则返回True
# print(all([1,2,3,4,0,''])) # False
# print(all([])) # True
# ************************************************************19
# any
# print(any([])) # False
# print(any([(),[],'',1]))
# ************************************************************20
# enumerate(iterable,start = 0),每次__next__返回一个元组(x_index,x)
# a = enumerate([12,3,34,5,4])
# print(list(a)) # [(0, 12), (1, 3), (2, 34), (3, 5), (4, 4)]
# b = enumerate([12,3,34,5,4],start=10)
# print(list(b)) # [(10, 12), (11, 3), (12, 34), (13, 5), (14, 4)]
# c = {'k1':'v1','k2':'v2'}
# print(list(enumerate(c))) # [(0, 'k2'), (1, 'k1')]
# print(list(enumerate(c.items()))) # [(0, ('k1', 'v1')), (1, ('k2', 'v2'))]
# print(list(c.items())) # [('k2', 'v2'), ('k1', 'v1')]
# print(list(enumerate(c.values()))) # [(0, 'v1'), (1, 'v2')]
# ************************************************************21
# set：可以用于列表去重
# 对list和tuple，如果要求去重后顺序不变，则用下面的代码：
# lst = [1,2,3,4,54,1,22,3,32,45,23,13,1]
# new_list = []
# for i in lst:
# if i not in new_list:
# new_list.append(i)
# print(new_list)
# ************************************************************22
# frozenset(iterable),将iterable对象转会为不可变的集合，可以作为字典的key
# print(frozenset([1,2,3])) # frozenset({1, 2, 3})
# print(frozenset('adsab')) # frozenset({'d', 'a', 'b', 's'})
# print(frozenset({1,23,4})) # frozenset({1, 4, 23})
# ************************************************************23
# slice
# a = slice(10) # a = slice(None, 10, None)
# a1 = slice(1,5) # a1 = slice(1, 5, None)
# a2 = slice(2,10,2) # a2 = slice(2, 10, 2)
# b = list(range(20))
# print(b[a]) # b[0:10]: [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
# print(b[a1]) # b[1:5]: [1, 2, 3, 4]
# print(b[a2]) # b[2:10:2]: [2, 4, 6, 8]
# ************************************************************24
# reversed
# a = [1,2,3,4523,23,42,34]
# b = reversed(a) # 返回一个迭代器
# print(list(b)) # [34, 42, 23, 4523, 3, 2, 1]
# print(a) # a 不变
# ************************************************************25
# memoryview:需要接收一个bytes object
# v= memoryview(bytes('hello,eva',encoding='utf-8'))
# print(v) # <memory at 0x0000025130B52F48>
# print(v[1]) # 101
# print(v[1:4])# <memory at 0x0000013B5A35E048>
# print(v[1:4].tobytes()) # b'ell'