Python Road (iv)-set collection

Set set set is an unordered and non-repeating collection of elements
Advantages: Fast access to solve repetitive problems

L1 = [1,2,34,5,6,7,4,3,3= set (L1)  #可以以列表元祖等作为参数传进来, the set set will automatically convert Cheng Yuanju and go back to
#输出结果:
{1, 2, 34, 4, 5, 6, 7, 3}

Various methods: Add,clear,..... Wait a minute

Add Merge Collection

L1 = [1,2,34,5,6,7,4,3,3= [23,3,4,5,100,2,3= set (L1)  # auto-convert and go to S2.add (  )print(S2)

Cear

L1 = [1,2,34,5,6,7,4,3,3= [23,3,4,5,100,2,3= set (L1)  # auto-convert and go to S2.add (  ) s2.clear ()print(S2)

Copy

L1 = [1,2,34,5,6,7,4,3,3= set (L1)  # automatic conversion and de-weight s3 = s2.copy ()Print  (S3)# output:{1, 2, 34, 4, 5, 6, 7, 3}

Difference  seeking difference set

L1 = [1,2,34,5,6,7,4,3,3= set (L1)  # automatic conversion and de-weight s2 = set ([12,3465,75,32,2#  The elements in the Loop S2 are compared to S1, and if there is no S1  , the elements in the loop S1 are compared with S2, and print prints (S1) are printed if there is no S3  Print(S4)# output:{4, 3465, 1, {34, 3, 5}

The difference between difference_update and difference is that it will update the original collection

L1 = [1,2,34,5,6,7,4,3,3= set (L1)  # automatic conversion and de-weight s2 = set ([12,3465,75,32,2]) S2.difference_update (S1)print(s2)# output:{32, 3465, 75, 12}

The Discard  parameter is a string or a number, and if the parameter is within the collection, it is deleted, and if it is not, nothing is done

#清除的元素不存在, do not take any action
L1 = [1,2,34,5,6,7,4,3,3,'a','AB']s1= Set (L1)#automatic conversion and de-weightS1.discard ('ABC')Print(S1)#Output Result:{1, 2, 34, 4, 5, 6, 7, 3,'a','AB'} #参数存集合内, the element is cleared L1= [1,2,34,5,6,7,4,3,3,'a','AB']s1= Set (L1)#automatic conversion and de-weightS1.discard ('AB')Print(S1)#Output Result:{1, 2, 34, 4, 5, 6, 7, 3,'a'}

Intersection the intersection between two combinations

L1 = [1,2,34,5,6,7,4,3,3,'a','ab'= set (L1)  # automatic conversion and de -s2 = set ([1,2,23,3,3,5,2= s2.intersection (S1)print(S3)  # output results:

{1, 2, 3, 5}

The Intersection_update function is the same as the intersection, except that it updates the original collection

L1 = [1,2,34,5,6,7,4,3,3,'a','ab'= set (L1)  # automatic conversion and de -s2 = set ([1,2,23,3,3,5,2]) s2.intersection_update (S1)print(S2) # Output Results {1, 2, 3, 5}

Isdisjoint returns True if there is no intersection, or false if not

L1 = [1,2,34,5,6,7,4,3,3,'a','AB']s1= Set (L1)#automatic conversion and de-weightS2 = Set ([1,2,23,3,3,5,2]) S3=s2.isdisjoint (S1)Print(S3)#Output ResultsFalsel1= [1,2,34,5,6,7,4,3,3,'a','AB']s1= Set (L1)#automatic conversion and de-weightS2 = Set ([111,222]) S3=s2.isdisjoint (S1)Print(S3)#Output ResultsTrue

If Issubset is  a subset, yes returns true, otherwise false

L1 = [1,2,34,5,6,7,4,3,3,'a','ab'= set (L1)  # automatic conversion and de -s2 = set ([111,222= s2.issubset (S1)print(S3)#  Output Result:False

Issuperset is the parent set, YES returns True, otherwise false

L1 = [1,2,34,5,6,7,4,3,3,'a','ab'= set (L1)  # automatic conversion and de -s2 = set ([111,222= s2.issuperset (S1)print(S3)#  Output Result:False

Pop randomly deletes an element and returns

L1 = [1,2,34,5,6,7,4,3,3,'a','ab','ds '  = set (L1)  # automatic conversion and de -s2 = s1.pop (2)print(S2) # Random result of output result

Remove removes a specified element and does not return

L1 = ['a','AB','DS']s1= Set (L1)#automatic conversion and de-weightS1.remove ('a')Print(S1)#Output Results{'AB','DS'}

Symmetric_difference symmetric difference, which refers to merging two sets and then finding the difference set

L1 = ['a','AB','DS']s1= Set (L1)#automatic conversion and de-weightS2 = Set ([1,2,3,4,'C','D','a']) S3=s1.symmetric_difference (S2) S4=s2.symmetric_difference (S1)Print(S3)Print(S4)#two times the result is the same.{1, 2, 3, 4,'D','C','AB','DS'}{1, 2, 3, 4,'D','DS','C','AB'}

Symmetric_difference_update is the same as the Symmetric_difference function, except that it updates the original collection

Update updates an element

L1 = ['a','AB','DS']s1= Set (L1)#automatic conversion and de-weightS1.update ('CD')Print(S1)#Output Result:{'D','AB','DS','a','C'}

Python Road (iv)-set collection