The path to python practice (six sets) and the path to python practice

Source: Internet
Author: User

The path to python practice (six sets) and the path to python practice

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Set

A set is an unordered, non-repeating data combination. Its main functions are as follows:

  • Deduplication: automatically removes duplicates when a list is changed to a set.
  • Test the relationship between the intersection, difference set, and union of the two groups of data.

 

Change List to set

list_1 = [1,4,5,7,3,6,7,9]
liset_1 = set(list_1)
print(list_1,type(list_1))

>>>

[1, 4, 5, 7, 3, 6, 7, 9] <class 'LIST'>

Process finished with exit cod

 

Intersection


List_1 = [,]
Liset_1 = set (list_1)

List_2 = set ([, 4])
Print (list_1, list_2)

List_1.intersection (list_2)
Print (list_1.intersection (list_2 ))
>>>

[4, 6]


Union

List_1 = [,]
Liset_1 = set (list_1)
List_2 = set ([, 4])
Print (list_1.union (list_2 ))
>>>
[,]


Difference set

List_1 = [,]
Liset_1 = set (list_1)
List_2 = set ([, 4])
Print (list_1.difference (list_2 ))

>>>

[1, 3, 5, 9, 7]


Subset

List_1 = [,]
Liset_1 = set (list_1)
List_2 = set ([, 4])
Print (list_1.issubset (list_2 ))

>>>

False

 

Parent set

List_1 = [,]
Liset_1 = set (list_1)
List_2 = set ([, 4])
Print (list_1.issuperset (list_2 ))

>>>

False

 

Symmetric Difference set

List_1 = [,]
Liset_1 = set (list_1)
List_2 = set ([, 4])
Print (list_1.issubset (list_2 ))

>>>

[0, 1, 2, 66, 3, 5, 7, 9, 22]

 

No Intersection

Print ("-----------")

List_3 = set ([1, 3, 7])

List_4 = set ([5, 6, 8])

Print (list_3.isdisjoint (list_4 ))

>>>

True

 

Of course, the operation can also be completed with symbols:

 

S = set ([,]) # create a numerical set

T = set ("Hello") # create a set of unique characters


A = t | s # The Union of t and s

B = t & s # intersection of t and s

C = t-s # calculate the difference set (the item is in t, but not in s)

D = t ^ s # symmetric difference set (the items are in t or s, but not both)



Basic operations:

T. add ('x') # add an item

S. update ([10, 37, 42]) # add multiple



You can use remove () to delete an item:

T. remove ('H ')


Len (s)
Set length

X in s
Test whether x is a member of s.

X not in s
Test whether x is not a member of s

S. issubset (t)
S <= t
Test whether every element in s is in t

S. issuperset (t)
S> = t
Test whether every element in t is in s

S. union (t)
S | t
Returns a new set containing every element of s and t.

S. intersection (t)
S & t
Returns a new set containing the public elements in s and t.

S. difference (t)
S-t
Returns a new set that contains elements in s but not in t.

S. symmetric_difference (t)
S ^ t
Returns a new set that contains no repeated elements in s and t.

S. copy ()
Returns a shortest copy of set "s ".

 

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