treeset

a natural sort of treeset: Steps: 1. Let the elements themselves have a comparative nature, 2. Implement Compareable interface, cover its CompareTo method Cases: class Student implementscomparable//first: Implement Compareable interface { Private String name; private int age; Replication constructor initialization name and age Student (String name,int age) { this. Name = name; this. Age = age; } public int compareTo (Object obj)//Second: Replication

In the Java language, the set interface has 3 common implementations HashSet : TreeSet,LinkedHashSet。 TreeSet is a collection of internal elements that can be sorted, using a red-black tree to store internal elements, sorted based on the values of the elements, which is slower than hashset.TreeSet requires the inner element to implement the comparable interface, because it is sorted according to the Compare

Set: Unordered, can not repeat element|--hashset: The data structure is a hash table, and the thread is non-synchronous.The principle of guaranteeing element uniqueness: Determining whether the hashcode value of an element is the sameIf same, the Equals method of the element will continue to be judged, whether true|--treeset: You can sort the elements in the Set collectionNote: When sorting, when the main conditions are the same, be sure to judge the

TREEMAP: package com; Import Java.util.Comparator; Import Java.util.TreeMap; public class Test5 { /** * @param args */public static void Main (string[] args) { //TODO Auto-gener Ated method Stub treemapif (O1 = = NULL | | | o2 = NULL) {return 0; } Return o1.tostring (). CompareTo (O2.tostring ()); } ); Tree.put ("K", "1"); Tree.put ("Ba", "2"); Tree.put ("Z", "3"); Tree.put ("D", "4"); Tree.put ("E", "5"); Tree.put ("An", "6

TreeSet implements the SortedSet also implements the set, but it is not a random object can be stored:public class Treesettest {public static void main (string[] args) {TreeSet tree = new TreeSet ();Tree.add (New Pepole ("Zhangsan"));Tree.add (New Pepole ("Lisi"));System.out.println (tree);}}class pepole{int age;String name;Public pepole (String name) {this.name

"One Minute Knowledge" HashSet and Treeset,hashmap and Hashtable HashSet and TreeSet HashSet Hash table is implemented, the data in the HashSet is unordered. There is no guarantee that the order of the elements may change. It's not synchronized. The collection element can be null but can only be placed in a null When an element is deposited into the HashSet collection, HashSet calls the object's Hashco

during compilation, but not duplicate objects, which are added only once for repeating elements. The order in which elements are added to the collection when the 2.Set set class program runs is not the order in which the collection is saved. Elements in the 3.TreeSet are stored in an orderly fashion, treeset each object's class must implement the comparable interface to use*/The

1. TreeSet guarantee Element uniqueness and comparator ordering principle and code implementation (comparator sort)(1)Student. Java:1 Packagecn.itcast_07;2 3 Public classStudent {4 PrivateString name;5 Private intAge ;6 7 PublicStudent () {8 Super();9 }Ten One PublicStudent (String name,intAge ) { A Super(); - This. Name =name; - This. Age =Age ; the } - - PublicString GetName () { -

1. TreeSet class overview:• ability to sort elements according to a certain rule.• or sort according to the comparator provided when the set was created• Depending on the construction method used2. code example:1 Packagecn.itcast_05;2 3 ImportJava.util.TreeSet;4 5 /*6 * TreeSet: Ability to sort elements according to a certain rule. 7 * There are two ways of sorting8 * A: Natural sort9 * B: Comparator sortT

calculate the value of the hashcode.TreeSet classTreeSet is the only implementation class for the SortedSet interface, and TreeSet ensures that the collection elements are in the sorted state. TreeSet supports two sorting methods, natural sorting and custom sorting, in which the natural sort is the default sorting method. The object that is added to the treeset

TreeSet is the only implementation class for SortedSet, as the SortedSet name implies,TreeSet allows the collection element to be in the orderly state. Compared with HashSet, TreeSet also provides the following methods (listed, mixed face cooked:)SortedSet subset (Object fromelement,object toelement): Returns the subset of this set, ranging from fromelement (incl

TreeSet: You can sort the elements in the Set collectionSorting is sorted according to ASCII.Import Java.util.iterator;import Java.util.treeset;public class Treesetdemo {public static void main (string[] args) {//T ODO auto-generated Method Stubmethod1 ();} public static void Method1 () {TreeSet ts = new TreeSet () Ts.add ("CBA"), Ts.add ("AAA"), Ts.add ("BCA"),

Some of the major features of TreeSet:1. The type stored in TreeSet must be consistent, cannot save int, and then save string2, TreeSet in the traversal of the collection elements, is the order of "from small to large" (my understanding, if the letters stored, sorted by dictionary order)3, Sort: When adding custom objects to