How to use merge in java

The merge() method in Java Collections merges two sorted ordered collections and generates a new sorted collection, maintaining the original order. Syntax: public static List merge(SortedMap a, SortedMap b). It accepts two sorted collections and returns a new collection containing all elements in sorted order. Note: The values ​​of duplicate keys will be merged according to the merge function, and the original collection will not be modified.

Introduction to the merge() method in Java

The merge() method is used in the Java Collections framework to merge two Static method for a sorted collection. It merges two sorted sets into a new sorted set, maintaining the original sort order.

Syntax

<code class="java">public static <T> List<T> merge(SortedMap<T, Double> a, SortedMap<T, Double> b)</code>

Parameters

• a: The first sorted collection
• b: The second sorted collection

Return value

A new sorted collection, Contains all elements in a and b, in sorted order.

Usage method

The merge() method can be used as follows:

<code class="java">import java.util.*;

public class MergeExample {

    public static void main(String[] args) {
        // 创建两个已排序的集合
        SortedMap<Integer, Double> map1 = new TreeMap<>();
        map1.put(1, 0.5);
        map1.put(3, 0.7);
        map1.put(5, 0.9);

        SortedMap<Integer, Double> map2 = new TreeMap<>();
        map2.put(2, 0.6);
        map2.put(4, 0.8);

        // 合并两个集合
        SortedMap<Integer, Double> mergedMap = Collections.merge(map1, map2, (a, b) -> a + b);

        // 打印合并后的集合
        System.out.println(mergedMap);
    }
}</code>

Output

<code>{1=0.5, 2=0.6, 3=0.7, 4=0.8, 5=0.9}</code>

In In this example, two sorted collections are merged into a new sorted collection that contains all elements and preserves the sorted order.

Notes

• If there are duplicate keys in the two collections, the merge() method will merge the values ​​according to the provided merge function.
• The merge() method does not modify the original collection. It creates a new collection as the result of the merge.

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