python学习 内建属性/内建函数/集合/functools

'''内建属性'''
class Idcast():
    def __init__(self,subject1):
        self.subject1=subject1
        self.subject2='hello'

    #属性访问时拦截器，打印log
    def __getattribute__(self, item):  #item---->属性
        print('====1>{}'.format(item))
        if item=='hh':
            print('嘿嘿')
            return 'hello subject1'
        else:
            temp=object.__getattribute__(self,item)
            print('====2>{}'.format(temp))
            return temp

    def show(self):
        print('this is Idcast')

s=Idcast('xxxxxx')
print(s.hh)
print(s.subject1)
print(s.subject2)
s.show()  #1、先获取show属性对应的结果，应该是一个方法；  2、方法()

#打印结果
# ====1>hh
# 嘿嘿
# hello subject1
# ====1>subject1
# ====2>xxxxxx
# xxxxxx
# ====1>subject2
# ====2>hello
# hello
# ====1>show
# ====2><bound method Idcast.show of <__main__.Idcast object at 0x000001A865911240>>
# this is Idcast

 

'''内建函数'''
#####map可根据可迭代对象，生成一个新的迭代对象#####
a=map(lambda x:x+x,[1,2,3])
for i in a:
    print(i) #打印结果为2,4,6

b=map(lambda x,y:x+y,[1,2,3],[4,5,6])
for i in b:
    print(i) #打印结果为5,7,9

def f1(x,y):
    return (x,y)
l1=[0,1,2,3,4,5,6]
l2=['sun','m','w','s','f','t','a']
c=map(f1,l1,l2)
for i in c:
    print(i)
# 打印结果
# (0, 'sun')
# (1, 'm')
# (2, 'w')
# (3, 's')
# (4, 'f')
# (5, 't')
# (6, 'a')


#####filter过滤筛选功能，最终返回的结果包含调用结果为True的元素#####
a=filter(lambda x:x%2,[1,2,3,4,5]) #0是False，1是True
for i in a:
    print(i) #打印结果为1,3,5

b=filter(None,'she') #不过滤，所有的东西全取
for i in b:
    print(i) #打印结果为s,h,e


#####reduce，可运用于累计和及阶乘####
from functools import reduce
a=reduce(lambda x,y:x+y,[1,2,3,4])
print(a) #打印结果为10

b=reduce(lambda x,y:x+y,[1,2,3,4],5)
print(b) #打印结果为15

c=reduce(lambda x,y:x+y,['aa','bb','cc'],'dd')
print(c) #打印结果为ddaabbcc


#####sort/sorted####
a=[12,34,53,3,22,1,4,456,44,66,690]

a.sort()
print(a)  #打印结果为[1, 3, 4, 12, 22, 34, 44, 53, 66, 456, 690]
a.sort(reverse=True)
print(a)  #打印结果为[690, 456, 66, 53, 44, 34, 22, 12, 4, 3, 1]

print(sorted(a))  #打印结果为[1, 3, 4, 12, 22, 34, 44, 53, 66, 456, 690]
b=sorted(a)
print(b)  #打印结果为[1, 3, 4, 12, 22, 34, 44, 53, 66, 456, 690]
print(sorted(a,reverse=True))  #打印结果为[690, 456, 66, 53, 44, 34, 22, 12, 4, 3, 1]
c=sorted(a,reverse=True)
print(c)  #打印结果为[690, 456, 66, 53, 44, 34, 22, 12, 4, 3, 1]

 

'''集合'''
a='abcdef'
A=set(a)
print(A)  #{'f', 'a', 'c', 'd', 'e', 'b'}

b='defghijk'
B=set(b)
print(B) #{'d', 'i', 'h', 'g', 'e', 'k', 'f', 'j'}

#交集
c=A&B
print(c)  #{'e', 'd', 'f'}

#并集
d=A|B
print(d)  #{'b', 'f', 'k', 'j', 'c', 'h', 'g', 'i', 'd', 'a', 'e'}

#差集
e=A-B
print(e)  #{'a', 'c', 'b'}

#对称差集
f=A^B
print(f)  #{'k', 'b', 'c', 'g', 'i', 'a', 'j', 'h'}

C=[1,2,3,3,5,3,4,5,6]
print(set(C))  #{1, 2, 3, 4, 5, 6}
print(list(set(C)))  #[1, 2, 3, 4, 5, 6]

 

'''functools'''
####偏函数functools.partial-省略参数的传递
import functools
def showarg(*args,**kwargs):
    print(args)
    print(kwargs)

p1=functools.partial(showarg,1,2,3)
p1()
p1(4,5,6)
p1(a='python',b='idcast')
print('=================')

p2=functools.partial(showarg,a=3,b='linux')
p2()
p2(1,2)
p2(a='python',b='idcast')

#打印结果
# (1, 2, 3)
# {}
# (1, 2, 3, 4, 5, 6)
# {}
# (1, 2, 3)
# {'a': 'python', 'b': 'idcast'}
# =================
# ()
# {'a': 3, 'b': 'linux'}
# (1, 2)
# {'a': 3, 'b': 'linux'}
# ()
# {'a': 'python', 'b': 'idcast'}