Set of Python basic data types

Set is a set of unordered and non-repeating elements, equivalent to a dictionary key, non-repeating, immutable

First, set Variable initialization

A = set () #注意在创建空集合的时候只能使用s =set () because s={} created an empty dictionary B = {"One", "one", "three", "four"}c = set (' boy ') D = set ([' Y ', ' b ', ' O ']) E  = Set ({"K1": ' v1 ', ' K2 ': ' V2 '}) F = {' K1 ', ' K2 ', ' k2 '}g = {(' K1 ', ' K2 ', ' K2 ')}print (A, type (a)) print (b, type (b)) print (C, Type (C)) print (d, type (d)) print (E, type (e)) print (F, type (f)) print (g, type (g)) Run Result: (set ([]), <type ' Set ' >) (Set ([ ' Four ', ' three ', ' one ', ' one ']), <type ' Set ' >) (set ([' Y ', ' b ', ' O ']), <type ' Set ' >) (set ([' Y ', ' b ', ' O ']), <t Ype ' Set ' >) (Set ([' K2 ', ' K1 ']), <type ' Set ' >) (Set ([' K2 ', ' K1 ']), <type ' Set ' >) (set ([' K1 ', ' K2 ', ' K2 ')]), <type ' Set ' >)

Second, set relationship

print e & f  # e  and  F  b of   print A | B  # A  and   print b -  A  #  differential Set (items in B, but not in A) print d ^ e  #  symmetric difference set (items in D or E, but not both)    Run Result: set ([' K2 ',  ' K1 ']) set ([' Four ',  ' one ',  ' three ',  ' "]) set ([' Four ',  ') One ',  ' three ',  ']) set ([' Y ',  ' K2 ',  ' K1 ' ",  ' B ',  ' O ']) 

x = set ([' I ',  ' e ',  ' m ',  ' d ',  ' t ']) y  = set (["I",  "D",  "E",  "a"]) print x.union (y)                  #  Set Set ([' E ',  ' d ',  ' I ',  ' h ',   ' j ',  ' m ',  ' t ']) print x.intersection (y)           #  intersection set ([' I ',  ' e ',  ' t ']) print x.difference (y)             #  difference Set Set ([' H ',  ' J ']) print x.symmetric_difference (y)  #  Symmetric differential operation result: Set ([' A ',  ' e ',  ' d ',  ' I ',  ' m ',  ' t ']) set ([' I ',  ' e ',  ' d ']) set ([' m ',   ' t ']) set ([' A ',  ' m ',  ' t ']) 

SE = set (["AA", "BB", "CC", "DD"]) ke = set (["AA", "BB"]) print se.difference (KE) # a exists, B does not exist, and a new sequence is generated SE.DIFFERENCE_UPDA Te (ke) # exists in, B does not exist, changes the original sequence print Seprint se.symmetric_difference (ke) # symmetric intersection, generates a new sequence se.symmetric_difference_update (KE) #对 Call intersection, update original sequence print SE run result: set ([' CC ', ' DD ']) set ([' CC ', ' DD ']) set ([' AA ', ' cc ', ' dd ', ' BB ']) set ([' AA ', ' BB ', ' cc ', ' DD '])

Third, the inclusion of the relationship

SE = set (["AA", "BB", "CC", "DD"]) ke = set (["AA", "BB"]) print Se.isdisjoint (KE) # Determine if two sets are not disjoint print se.issubset (KE) # judgment set is not included in the other collection, equivalent to A<=bprint se.issuperset (KE) # to determine whether the collection contains other collections, equivalent to the a>=b run result: falsefalsetrue

Iv. adding elements

SE = set (["AA", "BB", "CC"]) Ke = set ({"One", "X"}) Print Sese.add ("DD") # Add an element print sese.update (["DD", "EE"]) # Add multiple meta element print Sese.update (ke) # adds another collection of elements to print seset ([' AA ', ' cc ', ' BB ']) set ([' AA ', ' cc ', ' dd ', ' BB ']) set ([' AA ', ' BB ', ' cc ', ' DD ', ' ee ', ' DD ']) set ([' AA ', ' one ', ' + ', ' BB ', ' CC ', ' dd ', ' ee ', ' DD '])

V. Deleting elements

SE = set (["AA", "BB", "CC", "DD"]) se.discard ("AA") Print sese.remove ("BB") # element does not exist when an exception is thrown when print Sese.pop () # pops up a value that is random, cannot be specified Print SE Run results: set ([' CC ', ' dd ', ' BB ') ' Set ([' CC ', ' DD ']) set ([' DD '])

VI. Remove duplicate values

A = [one, one, one, one, one, one, 33]b = Set (a) print list (b) Run result: [33, 11, 44, 22, 55]

Vii. Common methods

Class set (mutableset[_t], generic[_t]):     def add (self, element:  _t)    #  Add an element     def clear (self)  #  empty collection      def copy (self)     def difference (self, *s: iterable[ Any])   # a exists in  b and returns a new set that can be assigned to other variables     def difference_update ( Self, *s: iterable[any])  # a exists in  b and changes the collection directly A    def discard (self, element: _t)  #   Delete single element     def intersection (self,  *s: iterable[any])     def intersection_update (self, *s: Iterable [Any])     def isdisjoint (Self, s: iterable[any])  #  determine if two sets are disjoint      def issubset (Self, s: iterable[any])  #  Determines whether a set is contained by another collection, equivalent to A<=b     dEf issuperset (Self, s: iterable[any])  #  Determines whether a collection contains other collections, equivalent to a>=b     def pop (self)  #  popup An element, random, not specified     def remove (self, element :  _t)  #  Remove a single element, if the element does not exist in the collection, it will error     def symmetric_difference (self, &NBSP;S:&NBSP;ITERABLE[_T])     def symmetric_difference_update (self, s:  ITERABLE[_T])     def union (self, *s: iterable[_t])      Def update (self, *s: iterable[_t])  #  Update individual elements, or other collections

This article is from the "Lifelong Learning" blog, please be sure to keep this source http://20120809.blog.51cto.com/10893237/1975068

Set of Python basic data types