Python data type, python

Python data type, python

1. Note the difference between list and set. set

List representation: list_1 = [1, 3, 4]; set representation: set_1 = set ()

List_1 = [1, 2, 3, 4, 23,4, 2] print (list_1, type (list_1) list_1 = set (list_1) print (list_1, type (list_1 )) list_2 = set ([2, 4, 6, 8, 10]) print (list_2, type (list_2) # running result [1, 2, 3, 4, 23, 4, 2] <class 'LIST'> {1, 2, 3, 4, 23} <class 'set'> {8, 2, 10, 4, 6} <class 'set'>

2. Set relationship:

########################### Link test part of a set ###### ############################ intersection print (list_1.intersection (list_2 )) # print (list_1.symmetric_difference (list_2) of the intersection of two sets except for the symmetric difference set # print (list_1.union (list_2) of the Union set # difference set # is in list_1, but not in list_2print (list_1.difference (list_2) # is in list_2, but not in list_1print (list_2.difference (list_1) # subset list_3 = set ([6, 8, 10]) print (list_3.issubset (list_2) # print (list_2.issuperset (list_3) # "" Return True if two sets have a null intersection. "print (list_1.isdisjoint (list_3) print (list_1.isdisjoint (list_2 ))'''

"& |-^" Another way to express the set relationship

# Intersection print ("intersection->", list_1 & list_2) # unionprint ("union->", list_1 | list_2) # differenceprint ("difference -->", list_1-list_2) # is in list_1 but not in list_2 # symmetric difference set print ("symmetric difference set -->", list_1 ^ list_2)

3. add, update, remove, len, in, not in, pop, discard

List_1 = (,) list_2 = ([,]) list_3 = set ([,]) print (list_1, type (list_1) print (list_2, type (list_2) print (list_3, type (list_3) #1. add an add item and add multiple updatelist_3.add (9) print ("test1 --", list_3) list_3.update ([11,13]) print ("test2 --", list_3) #2. remove a list_3.remove (11) print ("test3 --", list_3 )#. 3 length print ("test4 --", len (list_3) #4. print ("test5 ---", 6 in list_3, 3 in list_3, 11 not in list_3) #5. delete any set element and return print (list_3.pop () list_3.discard () # Remove an element from a set if it is a member. if the element is not a member, do nothing. list_3.remove () # Remove an element from a set; it must be a member. if the element is not a member, raise a KeyError