how to sort map by value.
This example explain how you sort map by key using java8 . Using java 8 we
do following steps
1. Convert a Map into a Stream
2. Sort it
3. Collect and return a new LinkedHashMap (keep the order)
example follows same steps coding as which explain below.
package Java8;
import java.util.Comparator;
import java.util.HashMap;
import java.util.LinkedHashMap;
import java.util.Map;
import java.util.stream.Collectors;
public class SortMapByValue {
public static void main(String[] args) {
Map<String, Integer> unsortMap = new HashMap<>();
unsortMap.put("z", 10);
unsortMap.put("b", 5);
unsortMap.put("r", 6);
unsortMap.put("a", 20);
unsortMap.put("d", 1);
unsortMap.put("e", 7);
unsortMap.put("y", 8);
unsortMap.put("n", 99);
unsortMap.put("g", 50);
unsortMap.put("m", 2);
unsortMap.put("f", 9);
unsortMap.put("a", 6);
System.out.println("Original...");
System.out.println(unsortMap);
//sort by values, and reserve it, 10,9,8,7,6...
Map<String, Integer> result = unsortMap.entrySet().stream()
.sorted(Map.Entry.comparingByValue(Comparator.reverseOrder()))
.collect(Collectors.toMap(Map.Entry::getKey, Map.Entry::getValue,
(oldValue, newValue) -> oldValue, LinkedHashMap::new));
//Alternative way
Map<String, Integer> result2 = new LinkedHashMap<>();
unsortMap.entrySet().stream()
.sorted(Map.Entry.<String, Integer>comparingByValue().reversed())
.forEachOrdered(x -> result2.put(x.getKey(), x.getValue()));
System.out.println("Sorted...");
System.out.println(result);
System.out.println( "Another way of sorting");
System.out.println(result2);
}
}
Output :----
Original...
{a=6, b=5, r=6, d=1, e=7, f=9, g=50, y=8, z=10, m=2, n=99}
Sorted...
{n=99, g=50, z=10, f=9, y=8, e=7, a=6, r=6, b=5, m=2, d=1}
Another way of sorting
{n=99, g=50, z=10, f=9, y=8, e=7, a=6, r=6, b=5, m=2, d=1}
how to sort map by value.
Reviewed by Mukesh Jha
on
8:27 PM
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