python 資料類型 --- 集合

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1. 注意列表和集合的區別 set

列表表現形式： list_1 = [1,3,4];  集合表現形式：set_1= set()

list_1 = [1,2,3,4,23,4,2]print(list_1,type(list_1))list_1 = set(list_1)print(list_1,type(list_1))list_2 = set([2,4,6,8,10])print(list_2,type(list_2))#運行結果[1, 2, 3, 4, 23, 4, 2] <class ‘list‘>{1, 2, 3, 4, 23} <class ‘set‘>{8, 2, 10, 4, 6} <class ‘set‘>

2. 集合的關係:

############################# 集合的關係測試 part ####################################交集print(list_1.intersection(list_2))#對稱差集  除去兩個集合的交集的那部分print(list_1.symmetric_difference(list_2))#並集print(list_1.union(list_2))#差集# is in list_1 , but not in list_2print(list_1.difference(list_2))# is in list_2, but not in list_1print(list_2.difference(list_1))#子集list_3 = set([6,8,10])print(list_3.issubset(list_2))#父集print(list_2.issuperset(list_3))#""" Return True if two sets have a null intersection. """print(list_1.isdisjoint(list_3))print(list_1.isdisjoint(list_2))‘‘‘

 "&  |  - ^ " 集合關係的另一種表示方法

#交集print("交集->", list_1 & list_2)#unionprint("並集->", list_1 | list_2)# differenceprint("difference-->",list_1 - list_2)  # is in list_1 but not in list_2#對稱差集print("對稱差集-->", list_1 ^ list_2)

3. 集合的方法 add , update , remove, len, in , not in , pop, discard

list_1 = (1,3,5,7)list_2 = ([1,3,5,7])list_3 = set([1,3,5,7])print(list_1,type(list_1))print(list_2,type(list_2))print(list_3,type(list_3))#1.添加一項 add, 添加多項updatelist_3.add(9)print("test1--",list_3)list_3.update([11,13])print("test2--",list_3)# 2.移走一項list_3.remove(11)print("test3--",list_3)#.3 長度print("test4--",len(list_3))# 4.在不在裡面print("test5---", 6 in list_3, 3 in list_3, 11 not in list_3)# 5.刪除任意的set element ，並返回print(list_3.pop())list_3.discard() # Remove an element from a set if it is a member.If the element is not a member, do nothing.list_3.remove() #Remove an element from a set; it must be a member. If the element is not a member, raise a KeyError

 

python 資料類型 --- 集合