Java/Collections Data Structure/TreeSet
Содержание
- 1 Add values to TreeSet<String>
- 2 Check if a particular value exists in Java TreeSet example
- 3 Comparable with a sorted collection.
- 4 Copy all elements of Java TreeSet to an Object Array Example
- 5 Creating a Sorted Set
- 6 Get Head Set from Java TreeSet example
- 7 Get lowest and highest value stored in Java TreeSet
- 8 Get Size of Java TreeSet
- 9 Get Sub Set from Java TreeSet
- 10 Get Synchronized Set from Java TreeSet example
- 11 Get Tail Set from Java TreeSet
- 12 Iterate through elements of Java TreeSet
- 13 Loop and remove element from a TreeSet
- 14 Remove all elements from Java TreeSet
- 15 Remove specified element from Java TreeSet
- 16 Sort items in a Set
- 17 TreeSet, SortedSet and HashSet
Add values to TreeSet<String>
<source lang="java">
import java.util.TreeSet; class TreeSetDemo {
public static void main(String args[]) { TreeSet<String> ts = new TreeSet<String>(); ts.add("C"); ts.add("A"); ts.add("B"); ts.add("E"); ts.add("F"); ts.add("D"); System.out.println(ts); }
}
</source>
Check if a particular value exists in Java TreeSet example
<source lang="java">
import java.util.TreeSet; public class Main {
public static void main(String[] args) { TreeSet<String> tSet = new TreeSet<String>(); tSet.add("1"); tSet.add("2"); tSet.add("3"); tSet.add("4"); tSet.add("5"); boolean blnExists = tSet.contains("3"); System.out.println("3 exists in TreeSet ? : " + blnExists); }
}
</source>
Comparable with a sorted collection.
<source lang="java">
import java.util.Set; import java.util.TreeSet; class Product implements Comparable<Product> {
String prodName; int prodID; Product(String str, int id) { prodName = str; prodID = id; } public int compareTo(Product p2) { return prodName.rupareToIgnoreCase(p2.prodName); } public boolean equals(Object p2) { return prodName.rupareToIgnoreCase(((Product) p2).prodName) == 0; }
} public class Main {
public static void main(String args[]) { Set<Product> prodList = new TreeSet<Product>(); prodList.add(new Product("A", 13546)); prodList.add(new Product("B", 04762)); prodList.add(new Product("C", 12221)); prodList.add(new Product("D", 44387)); for (Product p : prodList) System.out.printf("%-14s ID: %d\n", p.prodName, p.prodID); }
}
</source>
Copy all elements of Java TreeSet to an Object Array Example
<source lang="java">
import java.util.TreeSet; public class Main {
public static void main(String[] args) { TreeSet<Integer> tSet = new TreeSet<Integer>(); tSet.add(new Integer("1")); tSet.add(new Integer("2")); tSet.add(new Integer("3")); Object[] objArray = tSet.toArray(); for (Object obj: objArray){ System.out.println(obj); } }
}
</source>
Creating a Sorted Set
<source lang="java">
import java.util.Arrays; import java.util.Iterator; import java.util.Set; import java.util.TreeSet; public class Main {
public static void main(String[] argv) { // Create the sorted set Set<String> set = new TreeSet<String>(); set.add("b"); set.add("c"); set.add("a"); Iterator it = set.iterator(); while (it.hasNext()) { Object element = it.next(); System.out.println(element); } // Create an array containing the elements in a set String[] array = (String[]) set.toArray(new String[set.size()]); Arrays.toString(array); }
}
</source>
Get Head Set from Java TreeSet example
<source lang="java">
import java.util.SortedSet; import java.util.TreeSet; public class Main {
public static void main(String[] args) { TreeSet<String> tSet = new TreeSet<String>(); tSet.add("1"); tSet.add("2"); tSet.add("3"); tSet.add("4"); tSet.add("5"); SortedSet sortedSet = tSet.headSet("3"); System.out.println("Head Set Contains : " + sortedSet); }
}
</source>
Get lowest and highest value stored in Java TreeSet
<source lang="java">
import java.util.TreeSet; public class Main {
public static void main(String[] args) { TreeSet<String> tSet = new TreeSet<String>(); tSet.add("1"); tSet.add("2"); tSet.add("3"); tSet.add("4"); tSet.add("5"); System.out.println("Lowest value Stored in Java TreeSet is : " + tSet.first()); System.out.println("Highest value Stored in Java TreeSet is : " + tSet.last()); }
}
</source>
Get Size of Java TreeSet
<source lang="java">
import java.util.TreeSet; public class Main {
public static void main(String[] args) { TreeSet<Integer> tSet = new TreeSet<Integer>(); System.out.println("Size of TreeSet : " + tSet.size()); tSet.add(new Integer("1")); tSet.add(new Integer("2")); tSet.add(new Integer("3")); System.out.println(tSet.size()); // remove one element from TreeSet using remove method tSet.remove(new Integer("1")); System.out.println("Size of TreeSet after removal : " + tSet.size()); }
}
</source>
Get Sub Set from Java TreeSet
<source lang="java">
import java.util.TreeSet; import java.util.SortedSet; public class Main {
public static void main(String[] args) { TreeSet<String> tSet = new TreeSet<String>(); tSet.add("1"); tSet.add("2"); tSet.add("3"); tSet.add("4"); tSet.add("5"); SortedSet sortedSet = tSet.subSet("2", "5"); System.out.println("SortedSet Contains : " + sortedSet); }
}
</source>
Get Synchronized Set from Java TreeSet example
<source lang="java">
import java.util.Collections; import java.util.Set; import java.util.TreeSet; public class Main {
public static void main(String[] args) { TreeSet treeSet = new TreeSet(); Set set = Collections.synchronizedSet(treeSet); }
}
</source>
Get Tail Set from Java TreeSet
<source lang="java">
import java.util.SortedSet; import java.util.TreeSet; public class Main {
public static void main(String[] args) { TreeSet<String> tSet = new TreeSet<String>(); tSet.add("1"); tSet.add("2"); tSet.add("3"); tSet.add("5"); tSet.add("4"); SortedSet sortedSet = tSet.tailSet("2"); System.out.println("Tail Set Contains : " + sortedSet); }
}
</source>
Iterate through elements of Java TreeSet
<source lang="java">
import java.util.Iterator; import java.util.TreeSet; public class Main {
public static void main(String[] args) { TreeSet<Integer> tSet = new TreeSet<Integer>(); tSet.add(new Integer("1")); tSet.add(new Integer("2")); tSet.add(new Integer("3")); Iterator itr = tSet.iterator(); while (itr.hasNext()){ System.out.println(itr.next()); } }
}
</source>
Loop and remove element from a TreeSet
<source lang="java">
import java.util.Iterator; import java.util.Set; import java.util.TreeSet; public class TreeSetExample {
public static void main(String[] args) { // Create a new TreeSet Set<Integer> set = new TreeSet<Integer>(); // Add Items to the TreeSet set.add(new Integer(1)); set.add(new Integer(2)); set.add(new Integer(3)); set.add(new Integer(4)); set.add(new Integer(5)); set.add(new Integer(6)); set.add(new Integer(7)); set.add(new Integer(8)); set.add(new Integer(9)); set.add(new Integer(10)); // Use iterator to display the vsetes System.out.println("TreeSet Before: "); for (Iterator i = set.iterator(); i.hasNext();) { Integer integer = (Integer) i.next(); System.out.println(integer); } // Remove the integer 6 System.out.println("\nRemove Integer 6"); set.remove(new Integer(6)); // Use iterator to display the vsetes System.out.println("\nTreeSet After: "); for (Iterator i = set.iterator(); i.hasNext();) { Integer integer = (Integer) i.next(); System.out.println(integer); } }
}
</source>
Remove all elements from Java TreeSet
<source lang="java">
import java.util.TreeSet; public class Main {
public static void main(String[] args) { TreeSet<Integer> tSet = new TreeSet<Integer>(); tSet.add(new Integer("1")); tSet.add(new Integer("2")); tSet.add(new Integer("3")); System.out.println("TreeSet before removal : " + tSet); tSet.clear(); System.out.println("TreeSet after removal : " + tSet); System.out.println("Is TreeSet empty ? " + tSet.isEmpty()); }
}
</source>
Remove specified element from Java TreeSet
<source lang="java">
import java.util.TreeSet; public class Main {
public static void main(String[] args) { TreeSet<Integer> tSet = new TreeSet<Integer>(); tSet.add(new Integer("1")); tSet.add(new Integer("2")); tSet.add(new Integer("3")); System.out.println(tSet); System.out.println("Was 2 removed from TreeSet ? " + tSet.remove(new Integer("2"))); System.out.println(tSet); }
}
</source>
Sort items in a Set
<source lang="java">
import java.util.Set; import java.util.TreeSet; public class Main {
public static void main(String[] args) { Set<String> set = new TreeSet<String>(); set.add("Z"); set.add("A"); set.add("F"); set.add("B"); set.add("H"); set.add("X"); set.add("N"); for (String item : set) { System.out.print(item + " "); } }
}
</source>
TreeSet, SortedSet and HashSet
<source lang="java">
import java.util.HashSet; import java.util.Iterator; import java.util.Set; import java.util.SortedSet; import java.util.TreeSet; class SetDemo {
public static void main(String[] args) { String[] letters = { "A", "B", "C", "D", "E" }; Set s = new HashSet(); for (int i = 0; i < letters.length; i++) s.add(letters[i]); if (!s.add(letters[0])) System.out.println("Cannot add a duplicate.\n"); Iterator iter = s.iterator(); while (iter.hasNext()) System.out.println(iter.next()); System.out.println(""); SortedSet ss = new TreeSet(); for (int i = 0; i < letters.length; i++) ss.add(letters[i]); if (!ss.add(letters[0])) System.out.println("Cannot add a duplicate.\n"); iter = ss.iterator(); while (iter.hasNext()) System.out.println(iter.next()); }
}
</source>