14、内置函数、递归函数、匿名函数

一、内置函数

# print(abs(-1))# print(all([1,2,3]))# print(all([0,2,3]))

# print(all(‘‘))

# print(any([0,None,‘‘,1]))# print(any([0,None,‘‘]))# print(any([]))

# print(bin(3))# print(hex(17))# print(oct(9))

#0 None 空===》bool值为False，其余都为True

# def func():#     pass# print(callable(func))

# print(chr(68))# print(ord(‘D‘))

# res=complex(1+2j)# print(res.real)# print(res.imag)

#工厂函数# dict# int# str# set# list

# l=[] #l=list([])# list([1,2,3])# list([‘a‘])# list([‘b‘])

# l=[]# print(dir(l)) #查看一个对象下面的属性## print(help(l))

# print(divmod(1000,30))

# x=range(10)# enumerate([1,2,3]).__next__()

# cmd=‘print("你瞅啥")‘

# dic="{‘a‘:1,‘b‘:2}"# d=eval(dic)# print(type(d),d[‘a‘])

# with open(‘user.db‘,‘w‘,encoding=‘utf-8‘) as f:#     user_dic={‘name‘:‘egon‘,‘password‘:‘123‘}#     f.write(str(user_dic))

# with open(‘user.db‘,‘r‘,encoding=‘utf-8‘) as f:#     dic=f.read()#     print(dic,type(dic))#     dic=eval(dic)#     print(dic[‘name‘])

s={1,2} #s=set({1,2}) 定义可变集合

# s.add(3)# print(s)

# s=frozenset({1,2}) # 定义不可变集合

#哈希：# 1. 只要校验的内容一致，那hash得到结果永远一样# 2. 不可逆# 3. 只要采用的哈希算法一样，那无论被校验的内容有多长，hash的到的结果长度都一样# print(hash(‘asdfasdfsadf‘))# print(hash(‘asdfasdfsadf‘))

# x=1# y=x# print(id(x),id(y))## print(x is y) #判断的是身份

# a=1# b=1# print(a == b)  #判断的是值

# print(max([1,2,3,4]))

# print(pow(10,2,3))

l=[‘a‘,4,2,3]# for i in reversed(l):#     print(i)## print(list(reversed(l)))

# i=reversed(l)# for x in i:#     print(x)# print(list(i))

# print(round(3.141542653589127134,4))

# l=[‘a‘,‘b‘,‘c‘,‘d‘,‘e‘]# print(l[1:4:2])# s=slice(1,4,2)# print(l[s])

# vars() #等于locals()

# s=‘helloo‘# l=[1,2,3,4,5]## z=zip(s,l)# print(z)# for i in z:#     print(i)

import time

m=__import__(‘time‘) #以字符串的形式导入模块

# m.sleep(3000)

#面向对象里面讲super

isinstanceissubclass

classmethodstaticmethodproperty

delattrhasattrgetattr

二、递归函数

#递归调用：在函数调用过程中，直接或间接地调用了函数本身，这就是函数的递归调用

## def f1():#     print(‘from f1‘)#     f1()## f1()

# def f1():#     print(‘f1‘)#     f2()## def f2():#     f1()## f1()

# import sys# print(sys.getrecursionlimit())# print(sys.setrecursionlimit(1000000))## print(sys.getrecursionlimit())

# age(5)=age(4)+2# age(4)=age(3)+2# age(3)=age(2)+2# age(2)=age(1)+2# age(1)=18##### age(n)=age(n-1)+2       n>1# age(n)=18    n=1

# def age(n):#     if n == 1:#         return 18#     return age(n-1)+2## print(age(5))

#二分法

l = [1, 2, 10,33,53,71,73,75,77,85,101,201,202,999,11111]

def search(find_num,seq):    if len(seq) == 0:        print(‘not exists‘)        return    mid_index=len(seq)//2    mid_num=seq[mid_index]    print(seq,mid_num)    if find_num > mid_num:        #in the right        seq=seq[mid_index+1:]        search(find_num,seq)    elif find_num < mid_num:        #in the left        seq=seq[:mid_index]        search(find_num,seq)    else:        print(‘find it‘)

# search(77,l)# search(72,l)# search(-100000,l)

三、匿名函数

# def func(x,y):#     return x+y## func(1,2)

#匿名函数# f=lambda x,y:x+y# print(f)## print(f(1,2))## lambda x,y:x+y

#max,min,zip,sorted的用法salaries={‘egon‘:3000,‘alex‘:100000000,‘wupeiqi‘:10000,‘yuanhao‘:2000}

# print(max(salaries))# res=zip(salaries.values(),salaries.keys())## # print(list(res))# print(max(res))

# def func(k):#     return salaries[k]

# print(max(salaries,key=func))# print(max(salaries,key=lambda k:salaries[k]))# print(min(salaries,key=lambda k:salaries[k]))

# print(sorted(salaries)) #默认的排序结果是从小到到# print(sorted(salaries,key=lambda x:salaries[x])) #默认的排序结果是从小到到# print(sorted(salaries,key=lambda x:salaries[x],reverse=True)) #默认的排序结果是从小到到#

# x=1000# def f1():#     # global x#     x=0## f1()# print(x)

‘‘‘4. 内置函数    map    reduce    filter‘‘‘

# def func(f):#     return f## res=func(max)# print(res)

# l=[‘alex‘,‘wupeiqi‘,‘yuanhao‘]### res=map(lambda x:x+‘_SB‘,l)## print(res)## print(list(res))## nums=(2,4,9,10)## res1=map(lambda x:x**2,nums)## print(list(res1))

# from functools import reduce## l=[1,2,3,4,5]# print(reduce(lambda x,y:x+y,l,10))

# l=[‘alex_SB‘,‘wupeiqi_SB‘,‘yuanhao_SB‘,‘egon‘]## res=filter(lambda x:x.endswith(‘SB‘),l)# print(res)# print(list(res))