Question

How to convert ArrayList to LinkedHashMap in Java

Answer 1

import java.util.List;
import java.util.Arrays;
import java.util.LinkedHashMap;

// index as key

public class Example {
    public static void main(String[] args) {
        List<String> list = Arrays.asList("A", "B", "C");

        LinkedHashMap<Integer, String> map = new LinkedHashMap<>();

        for (int i = 0; i < list.size(); i++) {
            map.put(i, list.get(i));
        }

        System.out.println(map);
    }
}



/*
run:

{0=A, 1=B, 2=C}

*/

 

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Answer 2

import java.util.List;
import java.util.Arrays;
import java.util.LinkedHashMap;

// value as key

public class Example {
    public static void main(String[] args) {
        List<String> list = Arrays.asList("A", "B", "C");

        LinkedHashMap<String, Integer> map = new LinkedHashMap<>();
        
        for (int i = 0; i < list.size(); i++) {
            map.put(list.get(i), i);
        }


        System.out.println(map);
    }
}



/*
run:

{A=0, B=1, C=2}

*/

 

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