python函数，,set 添加一个无序

python函数，,set 添加一个无序

set 添加一个无序的，用set方法，访问速度快，天生解决了重复问题

1、difference 指定某个元素从原来set取出，并生成新的set

1 #difference2 a = set(["aaa","bbb","ccc","aaa"])3 print(a)4 b = a.difference(["aaa"])5 print(b)6 7 {‘ccc‘, ‘bbb‘, ‘aaa‘}8 {‘ccc‘, ‘bbb‘}

2、difference_update 删除原来set里某个元素

 1 #difference_update 2 a = set(["aaa","bbb","ccc","aaa"]) 3 print(a) 4 b = a.difference_update(["aaa"]) 5 print(a) 6 print(b) 7  8  9 {‘bbb‘, ‘ccc‘, ‘aaa‘}10 {‘bbb‘, ‘ccc‘}11 None

3、pop 删除某个元素

 1 #pop 2 a = set(["aaa","bbb","ccc","aaa"]) 3 print(a) 4 b = a.pop() 5 print(a) 6 print(b) 7  8  9 {‘aaa‘, ‘bbb‘, ‘ccc‘}10 {‘bbb‘, ‘ccc‘}11 aaa

4、remove 删除指定元素

 1 #remove 2 a = set(["aaa","bbb","ccc","aaa"]) 3 print(a) 4 b = a.remove("ccc") 5 print(a) 6 print(b) 7  8  9 {‘bbb‘, ‘ccc‘, ‘aaa‘}10 {‘bbb‘, ‘aaa‘}11 None

这里举一个例子，更新、删除、添加原来的表

 1 old_dict = { 2     "#1": {‘hostname‘: ‘c1‘, ‘cpu_count‘: 2, ‘mem_capicity‘: 80}, 3     "#2": {‘hostname‘: ‘c1‘, ‘cpu_count‘: 2, ‘mem_capicity‘: 80}, 4     "#3": {‘hostname‘: ‘c1‘, ‘cpu_count‘: 2, ‘mem_capicity‘: 80} 5 } 6 # cmdb 新汇报的数据 7 new_dict = { 8     "#1": {‘hostname‘: ‘c1‘, ‘cpu_count‘: 2, ‘mem_capicity‘: 800}, 9     "#3": {‘hostname‘: ‘c1‘, ‘cpu_count‘: 2, ‘mem_capicity‘: 80},10     "#4": {‘hostname‘: ‘c2‘, ‘cpu_count‘: 2, ‘mem_capicity‘: 80}11 }12 13 a = set(old_dict.keys())14 b = set(new_dict.keys())15 16 #要更新的数据17 update_set = a.intersection(b)18 print(update_set)19 #要删除的数据20 delete_set = a.symmetric_difference(update_set)21 print(delete_set)22 #要添加的数据23 add_set = b.symmetric_difference(update_set)24 print(add_set)25 26 27 28 {‘#3‘, ‘#1‘}29 {‘#2‘}30 {‘#4‘}

python函数