Definition, operation and operation of the collection (Python)

Definition of the collection:

The collection and the list ([]) are different from the dictionary ({}) and do not have a special syntax format. Can be created using set ().

A collection is as unordered as a dictionary. is also non-repeatable. So you can turn the list into a set to go heavy.

The set has special relationship performance, intersection, set, difference set, and so on.

#hanbb Come on!List1 = [1,4,5,7,3,6,7,9]# listS1 = set (List1)#remove Repeat,such as 7; Automatic de-weight (list converted to collection) S2= Set ([1,6,0,66,22,8,4])# another Express setS3 = Set ("Hello" # Is this the character that turns into a collection? Print(S3)#{' h ', ' O ', ' l ', ' e '}Print(S2)#{0, 2, 4, 6, 8, +}Print(S1)#{1, 3, 4, 5, 6, 7, 9}

The basic operation of a collection: new, removed, copied, length (no modification?) ）

#Basic Operation# ADD OneS1.add ('BB8')Print(S1)#{1, 3, 4, 5, 6, 7, ' BB8 ', 9} # Addmore S1.update ( [ "Pig","Monkey King"])# Note[]                     #{1, ' Monkey King ', 3, 4, 5, 6, 7, ' BB8 ', 9, ' Pig '}Print(S1)#s1.update(2,4,6) S1.update([2,4,6])                                       #{1, 2, 3, 4, 5, 6, 7, 9, ' pig ', ' BB8 ', ' Monkey King '}Print(S1) s1.update ("BB7")# Update "BB7" and add "BB8" difference obvious #{1, 2, 3, 4, 5, 6, 7, 9, ' 7 ', ' BB8 ', ' Monkey King ', ' pig ', ' B '}Print(S1)#Remove#S1.remove ("1", "2", "3") # can not remove multiple # remove () takes exactly one argument (3 given)#s1.remove (' 1 ') # data will go wrong, why Yes # s1.remove (' 1 ')S1.remove ('B')# Letters don't, Chinese characters don't                             #{1, 2, 3, 4, 5, 6, 7, 9, ' pig ', ' Monkey King ', ' BB8 ', ' 7 '}Print(S1)#CopyS4 =s2.copy ()Print(S2)#lengthPrint(Len (S1))# A

The relational operation of the set: intersection, set, difference (two of the set position has influence), symmetric difference set.

#RelationshipPrint(S1.intersection (S2))#{1, 4, 6}Print(S1.union (S2))#{0, 1, 2, 3, 4, 5, 6, 7,, 9, 8, ' 7 ', ' BB8 ', 22, ' pig ', ' Monkey King '}Print(S1.difference (S2)) # in 1, not in 2#{' BB8 ', 2, 3, ' 7 ', 5, 7, 9, ' Monkey King ', ' Pig '}Print(S2.difference (S1)) # in 2, not in 1#{0, 8, $, $}Print(S1.symmetric_difference (S2)) # Symmetric difference sets (items in t or S, but not both) # {0, 66, 2, ' 7 ', 3, 5, 8, 7, 9, ' Monkey King ', 22, ' pig ', ' BB8 '}

Access to collection values:

#Accessing collection ValuesPrint("1" inchS1)#FalsePrint("BB8" inchS1)#True

Print("1"  not inchS1)#True forIinchS1:Print(i)" "1234567 Monkey King 9bb87 Pig" "

The collection is also relatively easy to understand and master, as well as operational symbols.

Definition, operation and operation of the collection (Python)