Use the size() method of the TreeSet class to get the number of elements in the tree collection

Title: Use the size() method of the TreeSet class to obtain the number of elements in the tree collection

Introduction

TreeSet is an ordered collection in the Java collection framework, which implements SortedSet The interface is implemented using a red-black tree data structure. TreeSet can be sorted according to the natural order of elements, or by using a Comparator custom comparator. This article will introduce how to use the size() method of the TreeSet class to obtain the number of elements in the tree collection, and provide corresponding code examples.

The size() method of the TreeSet class

The TreeSet class inherits from the AbstractSet abstract class and implements the SortedSet interface. It provides a series of methods to operate on ordered collections. The size() method is one of the most commonly used methods. It is used to obtain the number of elements in a collection and returns an integer value of type int.

Code Example

The following is a simple example that shows how to use the size() method of the TreeSet class to get the number of elements in the tree collection:

import java.util.TreeSet;

public class TreeSetExample {
    public static void main(String[] args) {
        TreeSet<String> treeSet = new TreeSet<>();

        // 向TreeSet中添加元素
        treeSet.add("apple");
        treeSet.add("banana");
        treeSet.add("orange");

        // 获取TreeSet中的元素数量
        int size = treeSet.size();
        System.out.println("TreeSet的元素数量：" + size);
    }
}

The above code first A TreeSet object is created, and three elements are added to the set using the add() method. Finally, use the size() method to get the number of elements in the collection and print the result.

Running results

Run the above code and get the following output:

TreeSet的元素数量：3

Summary

This article introduces how to use the size() method of the TreeSet class to obtain The number of elements in the tree collection. By calling this method, we can easily obtain the number of elements in the collection, which facilitates subsequent operations. I hope this article can help you understand the use of the TreeSet class.

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