. 1 # ! / Usr / bin / Python the env
2 # __author: HLC
. 3 # DATE: 2019/6/1
. 4
. 5 # SET set
6 # set to form a set of different elements together, python type foundation when set
7 # Composition members of the collection can not be repeated
. 8 # a = [1,2,3,4,5,1,2,3,4,5, "a", "a", "a", "B", "B" " B "," C "]
. 9 # B = set (A) # keys are defined by a set of set
10 # Print (A) # [. 1, 2,. 3,. 4,. 5,. 1, 2,. 3,. 4,. 5, 'A', 'A', 'A', 'B', 'BB', 'C']
. 11 # Print (B) # {. 1, 2,. 3,. 4,. 5, 'A', 'BB', 'c', 'b'}
12 is
13 is # can hash value collection object a disordered array: set members can do dictionary keys
14 #a = [[ "asdf", 1244], 1,2,3,4,5,1,2,3,4,5, "a", "a", "a", "b", "b" "B", "C"]
15 # B = sET (A) # TypeError: unhashable type: 'List'
16 # Print (B)
. 17
18 is # cLASSIFICATION: set variable, the set of immutable
19 # variable set, add and remove elements, non-hash, dictionary keys can not be used, the other can not be set as an element, the opposite set of immutable
20 is # a = [l, 2,3]
21 is # B = sET (a ) # TypeError: unhashable type: 'set'
22 is # C = {B: "SDF"}
23 is
24 # Create a set of
25 # because there is no collection of its own syntax, the method can only be set by the factory set () and frozenset ( ) created
26 # s1 = the SET ( "asfd")
27 # s2 = frozenset("dsg")
28 # Print (S1, type (S1)) # { 'F', 'D', 'A', 'S'} <class' SET '>
29 # Print (S2, type (S2) # frozenset ({' D ',' G ',' S '}) <class' frozenset'>
30
31 is # access set
32 # Since the collection itself is disordered, so can not create an index or as a set of slice operation, or only used in loops through , not in access or judged collection elements.
33 is # S1 = sET ( "asdfsd")
34 is # Print ( "A" in S1) # True
35 # S1 [0] # TypeError: 'sET' Object IS Not subscriptable
36
37 [ # for i in s1:
38 # print(i)
39 # d
40 # s
41 # a
42 is # F
43 is
44 is # update the collection, the following can be built using Method:
45 # S1 = SET ( "asdf")
46 is # s1.add ()
47 # s1.update ()
48 # s1.remove ()
49 # only the variable set in order to update
50 # S1 = frozenset ( "gdsfg")
51 is # # s1.add () # AttributeError: 'frozenset' Object attribute has NO 'the Add'
52 is
53 is # S2 = sET ( "SDF")
54 is # s2.add # ( "MMN") {# 'F', 'MMN', 'D', 'S'}
55 # s2.update ( "JKL") {# 'D', 'L','s', 'k', 'j', 'f'}
56 #Print (S2)
57 is
58 # S1 = SET ([ "asdf", 325, "456"])
59 # # s1.remove (325) # { '456', 'asdf'}
60 # s1.pop () # { 'asdf', 325}
61 is # s1.clear () # sET ()
62 is # del NameError # S1: name 'S1' iS Not defined
63 is # Print (S1)
64
65 # collection type operator
66 # in, in not
67 # collection is equivalent to not equivalent (==,! =)
68 # subset of the superset
69 # Print (the sET ( "asd") == the sET ( "asdasd")) True #
70 # S = the sET ( "adsfas")
71 #S1 = SET ( "ADS")
72 # Print ( "S" in S) # True
73 is # Print (S> S1) # True
74
75 # joint (|) or operating joint (Union) operation with a set of fact and the like price, there is a combined symbol equivalent methods, Union ()
76 # S1 = SET ( "qewr")
77 # S2 = SET ( "ghkj")
78 # S3 = S1 | S2
79 # Print (S3) {# 'E', 'K', 'R & lt', 'H', 'W', 'G', 'Q', 'J'}
80 # Print (s1.union (S2)) {# 'E', ' K ',' R & lt ',' H ',' W ',' G ',' Q ',' J '}
81
82 A = SET ([1,2,3,4,5])
83 b = set([4,5,6,7,8])
84
85 #Intersection intersrction () is equivalent to B & A
86 # Print (a.intersection (B)). 4 {#,}. 5
87 # and union set equal to A | B
88 # Print (a.union (B)). 1 {# , 2, 3, 4, 5, 6, 7, 8}
89 # difference current equivalent to the difference A - B
90 # Print (a.difference (B)) {#. 1, 2, 3}
91 is # Print (B. -difference (A)) {#. 8,. 6,}. 7
92 # symmetric difference (reverse intersection) The symmetric_difference equivalent ^ B A
93 # Print (a.symmetric_difference (B)) {#. 1, 2,. 3,. 6, 7, 8}
94 # superset superset
95 # Print (a.issuperset (B)) #> False
96 # subset
97 # print(a.issubset(b)) # < False