Day3 set sets, functions, and adorners

Set characteristics: unordered, non-repeating, can be nested

Create set
Set_example = Set ("123", "213", "234", "432")
S1 = [11,22,33,44,11,22,33]
S2 = set (S1)
Print (s2)

The list () is equivalent to the execution of the constructor method __int__, which executes a for loop, loop (11,22,33,44,11,22,33) Set difference
S1 = {11, 33, 44, 66}
S2 = {22, 33, 44, 55, 88}

S1 exists in the S2
S3 = s1.difference (S2)
Print (S3)

Variance results updated to S1

S1.difference_update (S2)
Print (S1)

S1.symmetric_difference_update (S2)

Print (S1)

Removes the specified element, there is a removal, there is no action, discard most useful

S1.discard (11)
Print (S1)

Removes the specified element without an error

S1.remove (11111)

Random removal

S1 = {11, 33, 44, 66}
S3 = S1.pop ()
Print (S1)
Print (S3)

Intersection

S3 = s1.intersection (S2)
Print (S3)

Intersection update to S1

S1.intersection_update (S2)
Print (S1)

Whether the parent-child sequence

S1.issubset (S2)
S1.issuperset (S2)

and set

S3 = s1.union (S2)
Print (S3)

Cyclic updates (strings, lists, tuples) are objects that can be used for loops

S1.update ([11,22,33,44,55,66,77,88,99,00])
Print (S1)

Set Exercises

Old_dict = {
    "#1": 8,
    "#2": 4,
    "#4": 2,
}

New_dict = {
    "#1": 4,
    "#2": 4,
    "#3": 2,
}
#应该删除哪几个槽位
Old_set = Set (Old_dict.keys ())
New_set = Set (New_dict.keys ())
Old_set.difference ()
#需要删除的, there is no new in old.
Remove_set = Old_set.difference (New_set)
Print ("Slot to delete:%s"% remove_set)
#需要增加的, there's old in new.
Add_set = New_set.difference (Old_set)
Print ("Additional Slots required:%s"% add_set)
#需要更新的, the intersection of old and new
Update_set = Old_set.intersection (New_set)
Print ("Slots required for update:%s"% update_set)

Day3 set sets, functions, and adorners