标签：
set
set集合，是一个无序且不重复的元素集合，集合对象还支持union(联合), intersection(交), difference(差)和sysmmetric difference(对称差集)等数学运算.
不重复性
1 >>> a = [1,1,2,2,3,3,4,4,] 2 >>> set(a) 3 {1, 2, 3, 4}
无序性
1 #!/usr/bin/python 2 # -*- coding: UTF-8 -*- 3 a = [‘gong‘,‘shang‘,‘jue‘,‘zhi‘,‘yu‘,] 4 b = set(a) 5 print(b) 6 7 #输出结果 8 {‘zhi‘, ‘yu‘, ‘gong‘, ‘shang‘, ‘jue‘}
set（object）
1.def difference(self,*args,**kwargs): # difference()用来查找a中存在，而b中不存在的元素
1 a = set([‘gong‘,‘shang‘,‘jue‘,‘zhi‘,‘yu‘]) 2 b = set([‘gong‘,‘jue‘,‘yu‘,‘wen‘,‘wu‘]) 3 c = a.difference(b) 4 print(c) 5 6 # 输出结果 7 {‘zhi‘, ‘shang‘}
2.def intersection(self,*args,**kwargs): # instersection()用来查找a,b中共同存在的元素（交集）
1 a = set([‘gong‘,‘shang‘,‘jue‘,‘zhi‘,‘yu‘]) 2 b = set([‘gong‘,‘jue‘,‘yu‘,‘wen‘,‘wu‘]) 3 c = a.intersection(b) 4 print(c) 5 6 # 输出结果 7 {‘gong‘, ‘jue‘, ‘yu‘}
3.def symmetric_difference(self,*args,**kwargs): # symmetric_difference()用来查找对称差集，即a，b中不想交的元素，与instersection()相反
1 a = set([‘gong‘,‘shang‘,‘jue‘,‘zhi‘,‘yu‘]) 2 b = set([‘gong‘,‘jue‘,‘yu‘,‘wen‘,‘wu‘]) 3 c = a.symmetric_difference(b) 4 print(c) 5 6 #输出结果 7 {‘shang‘, ‘wen‘, ‘zhi‘, ‘wu‘}
4.def discard(self,*args,**kwargs):及 def remove(self,*args,**kwargs): # discard()用来删除指定元素，元素不存在不报错，remove()也是用来删除指定元素，但是元素不存在会报错
1 a = set([‘gong‘,‘shang‘,‘jue‘,‘zhi‘,‘yu‘]) 2 a.discard(‘gong‘) 3 print(a) 4 5 #输出结果 6 {‘jue‘, ‘yu‘, ‘shang‘, ‘zhi‘} 7 8 a = set([‘gong‘,‘shang‘,‘jue‘,‘zhi‘,‘yu‘]) 9 a.discard(‘wu‘) 10 print(a) 11 12 #输出结果 13 #为空，没有报错 14 15 16 a = set([‘gong‘,‘shang‘,‘jue‘,‘zhi‘,‘yu‘]) 17 a.remove(‘shang‘) 18 print(a) 19 20 #输出结果 21 {‘gong‘, ‘zhi‘, ‘jue‘, ‘yu‘} 22 23 a = set([‘gong‘,‘shang‘,‘jue‘,‘zhi‘,‘yu‘]) 24 a.remove(‘wu‘) 25 print(a) 26 27 #输出结果 28 #报错 29 Traceback (most recent call last): 30 File "C:/Users/Administrator/PycharmProjects/untitled4/mxzheng/a/a1.py", line 9, in <module> 31 a.remove(‘wu‘) 32 KeyError: ‘wu‘
5.def update(self,*args,**kwargs): # update()用来更新
1 a = set([‘gong‘,‘shang‘,‘jue‘,‘zhi‘,‘yu‘]) 2 b = set([‘ma‘,‘xiao‘,‘zheng‘]) 3 a.update(b) 4 print(a) 5 6 #输出结果 7 {‘gong‘, ‘zhi‘, ‘ma‘, ‘jue‘, ‘yu‘, ‘shang‘, ‘zheng‘, ‘xiao‘}
6.def union(self,*args,**kwargs): # union()用来查找a,b中所有元素（并集）
1 a = set([‘gong‘,‘shang‘,‘jue‘,‘zhi‘,‘yu‘]) 2 b = set([‘wen‘,‘wu‘,‘shen‘,‘shang‘]) 3 c = a.union(b) 4 print(c) 5 6 #输出结果 7 {‘shen‘, ‘wu‘, ‘yu‘, ‘zhi‘, ‘wen‘, ‘jue‘, ‘gong‘, ‘shang‘}
7.def intersection_update(self,*args,**kwargs): # intersection_update() 查找a,b的交集并更新到a
1 a = set([‘gong‘,‘shang‘,‘jue‘,‘zhi‘,‘yu‘]) 2 b = set([‘shen‘,‘shang‘]) 3 a.intersection_update(b) 4 print(a) 5 6 #输出结果 7 {‘shang‘}
8.def symmetric_difference_update(self,*args,**kwargs): # symmetric_difference_update() 查找a，b的对称差集，并更新到a
1 a = set([‘gong‘,‘shang‘,‘jue‘,‘zhi‘,‘yu‘]) 2 b = set([‘shen‘,‘shang‘]) 3 a.symmetric_difference_update(b) 4 print(a) 5 6 #输出结果 7 {‘zhi‘, ‘gong‘, ‘yu‘, ‘shen‘, ‘jue‘}
9.def issubset(self,*args,**kwargs):和 def issuperset(self,*args,**kwargs): # issubset用来查看b是否为a的子序列，issuperset()用来查看a是否为b的父序列，返回结果True or False
1 a = set([‘gong‘,‘shang‘,‘jue‘,‘zhi‘,‘yu‘]) 2 b = set([‘gong‘,‘shang‘]) 3 c = a.issubset(b) 4 print(c) 5 6 #输出结果 7 False 8 ... 9 a = set([‘gong‘,‘shang‘,‘jue‘,‘zhi‘,‘yu‘]) 10 b = set([‘gong‘,‘shang‘]) 11 c = b.issubset(a) 12 print(c) 13 14 #输出结果 15 True 16 17 ... 18 a = set([‘gong‘,‘shang‘,‘jue‘,‘zhi‘,‘yu‘]) 19 b = set([‘gong‘,‘shang‘]) 20 c = a.issuperset(b) 21 print(c) 22 23 #输出结果 24 Ture 25 26 a = set([‘gong‘,‘shang‘,‘jue‘,‘zhi‘,‘yu‘]) 27 b = set([‘gong‘,‘shang‘]) 28 c = b.issuperset(a) 29 print(c) 30 31 #输出结果 32 False
10.def add(self,*args,**kwargs): #add() #用来添加元素
1 a = set([‘gong‘,‘shang‘,‘jue‘,‘zhi‘,‘yu‘]) 2 b = (1,2,3,4,5) 3 a.add(b) 4 print(a) 5 6 #输出结果 7 {‘zhi‘, (1, 2, 3, 4, 5), ‘gong‘, ‘jue‘, ‘shang‘, ‘yu‘}
11.def clear(self,*args,**kwargs): #用来清除集合中所有的元素
1 a = set([‘gong‘,‘shang‘,‘jue‘,‘zhi‘,‘yu‘]) 2 a.clear() 3 print(a) 4 5 #输出结果 6 set()
12.def difference_update(self,*args,**kwargs): # 从a集合中从删除和b的交集
1 a = set([‘gong‘,‘shang‘,‘jue‘,‘zhi‘,‘yu‘]) 2 b = set([‘gong‘,‘shang‘]) 3 a.difference_update(b) 4 print(a) 5 6 #输出结果 7 {‘yu‘, ‘zhi‘, ‘jue‘}
标签：
原文地址：http://www.cnblogs.com/mxzheng/p/5519561.html
