set 是一个无序且不重复的元素集合
访问速度快
解决了重复问题
1 def add(self, *args, **kwargs): # real signature unknown 添加 2 """ 3 Add an element to a set. 4 5 This has no effect if the element is already present. 6 """ 7 pass
例：
s1 = set() s1.add('xiaolong') print(s1) s1.add('xiaolong') print(s1)
得：
{'xiaolong'}
{'xiaolong'}
8 9 def clear(self, *args, **kwargs): # real signature unknown清空所有数据 10 """ Remove all elements from this set. """ 11 pass
12 13 def copy(self, *args, **kwargs): # real signature unknown浅拷贝 14 """ Return a shallow copy of a set. """ 15 pass
16 17 def difference(self, *args, **kwargs): # real signature unknown比对两个set之间的不同、得到一个新set 18 """ 19 Return the difference of two or more sets as a new set. 20 21 (i.e. all elements that are in this set but not the others.) 22 """ 23 pass
例:
s2 = set(['alex', 'eric', 'tony','alex']) print(s2) s3 = s2.difference(['alex', 'eric']) print(s2) print(s3)
得：
{'tony', 'alex', 'eric'}
{'tony', 'alex', 'eric'}
{'tony'}
24 25 def difference_update(self, *args, **kwargs): # real signature unknown更新本身数据集合、把传进来的数据和本身一样的删掉，没有返回值（删除当前set中的所有包含在 参数集合 里的元素） 26 """ Remove all elements of another set from this set. """ 27 pass
例：
s2 = set(['alex', 'eric', 'tony','alex']) print(s2) s4 = s2.difference_update(['alex', 'eric'])#更新了自己、把以前的和传进来的相同的移除 print(s2) print(s4)
得：
{'alex', 'tony', 'eric'}
{'tony'}
None
28 29 def discard(self, *args, **kwargs): # real signature unknown移除元素 30 """ 31 Remove an element from a set if it is a member. 32 33 If the element is not a member, do nothing. 34 """ 35 pass
36 37 def intersection(self, *args, **kwargs): # real signature unknown取交集，创建一个新的set 38 """ 39 Return the intersection of two sets as a new set. 40 41 (i.e. all elements that are in both sets.) 42 """ 43 pass 44
45 def intersection_update(self, *args, **kwargs): # real signature unknown取交集、修改原来的set 46 """ Update a set with the intersection of itself and another. """ 47 pass
48 49 def isdisjoint(self, *args, **kwargs): # real signature unknown如果没有交集、返回true 50 """ Return True if two sets have a null intersection. """ 51 pass
52 53 def issubset(self, *args, **kwargs): # real signature unknown是否是子集 54 """ Report whether another set contains this set. """ 55 pass
56 57 def issuperset(self, *args, **kwargs): # real signature unknown是否是父集 58 """ Report whether this set contains another set. """ 59 pass
60 61 def pop(self, *args, **kwargs): # real signature unknown移除 62 """ 63 Remove and return an arbitrary set element. 64 Raises KeyError if the set is empty. 65 """ 66 pass 67 68 def remove(self, *args, **kwargs): # real signature unknown移除 69 """ 70 Remove an element from a set; it must be a member. 71 72 If the element is not a member, raise a KeyError. 73 """ 74 pass
例：
s2 = set(['alex', 'eric', 'tony','alex']) print(s2) s2.remove('alex') print(s2)
得：
{'eric', 'tony', 'alex'}
{'eric', 'tony'}
75 76 def symmetric_difference(self, *args, **kwargs): # real signature unknown差集、创建新对象 77 """ 78 Return the symmetric difference of two sets as a new set. 79 80 (i.e. all elements that are in exactly one of the sets.) 81 """ 82 pass
83 84 def symmetric_difference_update(self, *args, **kwargs): # real signature unknown差集、改变原来 85 """ Update a set with the symmetric difference of itself and another. """ 86 pass 87
88 def union(self, *args, **kwargs): # real signature unknown并集 89 """ 90 Return the union of sets as a new set. 91 92 (i.e. all elements that are in either set.) 93 """ 94 pass 95 96 def update(self, *args, **kwargs): # real signature unknown更新 97 """ Update a set with the union of itself and others. """ 98 pass
实例：寻找差异
# 数据库中原有 old_dict = { "#1":{ 'hostname':c1, 'cpu_count': 2, 'mem_capicity': 80 }, "#2":{ 'hostname':c1, 'cpu_count': 2, 'mem_capicity': 80 } "#3":{ 'hostname':c1, 'cpu_count': 2, 'mem_capicity': 80 } } # cmdb 新汇报的数据 new_dict = { "#1":{ 'hostname':c1, 'cpu_count': 2, 'mem_capicity': 800 }, "#3":{ 'hostname':c1, 'cpu_count': 2, 'mem_capicity': 80 } "#4":{ 'hostname':c2, 'cpu_count': 2, 'mem_capicity': 80 } }
交集、差集
old_dict.keys()
new_dict.keys()
交集：要更新的数据
差集：
原来，要更新
old = set(old_dict.keys())
new = set(new_dict.keys())
update_set = old.intersection(new)
delete_set = old.symmetric_difference(update_set)
add_set = new.symmetric_difference(update_set)
#交集(更新)
update_set = old.intersection(new)
#差集
difference 获取自己没有的、如果update_set 比它多、就没办法准备得到结果
deleta_set = old.difference(update_set)
for item in old:
if item in update_set:
del "old.item"
add_set = new.difference(update_set)
#对称差
delete_set = old.symmetric_difference(update_set)
add_set = new.symmetric_difference(update_set)
例：
s1 = set([11,22,33]) s2 = set([22,44]) ret1 = s1.difference(s2) ret2 = s1.symmetric_difference(s2) print(ret1) print(ret2)
得：
{33, 11}
{33, 11, 44}
#差集
delete_set = old.difference(new)
add_set = new.symmetric_difference(update_set)
#数据库中原有 old_dict = { "#1": {'hostname': 'c1', 'cpu_count': 2, 'mem_capicity': 80}, "#2": {'hostname': 'c1', 'cpu_count': 2, 'mem_capicity': 80}, "#3": {'hostname': 'c1', 'cpu_count': 2, 'mem_capicity': 80} } # cmdb 新汇报的数据 new_dict = { "#1": {'hostname': 'c1', 'cpu_count': 2, 'mem_capicity': 800}, "#3": {'hostname': 'c1', 'cpu_count': 2, 'mem_capicity': 80}, "#4": {'hostname': 'c1', 'cpu_count': 2, 'mem_capicity': 80} } old_set = set(old_dict.keys())#把old_dict的键转换成set update_list = list(old_set.intersection(new_dict.keys()))#取交集、创建一个新的set、最后得到一个新的列表、这是要 更新 new_list = [] del_list = [] for i in new_dict.keys(): if i not in update_list: new_list.append(i)#判断新字典里i是否在update_list（要删除的里面），如果不在添加到new_list列表里面这是需要新建 for i in old_dict.keys(): if i not in update_list: del_list.append(i)#判断旧字典i是否在update_list(要删除的里面），如果不在添加到del_list里列表里面这是需要删除 print(update_list,new_list,del_list)
得：
['#3', '#1'] ['#4'] ['#2']