Java sort HashMap by value
31,857
Solution 1
You have to create a custom comparator like this:
import java.util.Comparator;
import java.util.Arrays;
public class Test {
public static void main(String[] args) {
String[] strings = {"Here", "are", "some", "sample", "strings", "to", "be", "sorted"};
Arrays.sort(strings, new Comparator<String>() {
public int compare(String s1, String s2) {
int c = s2.length() - s1.length();
if (c == 0)
c = s1.compareToIgnoreCase(s2);
return c;
}
});
for (String s: strings)
System.out.print(s + " ");
}
}
Solution 2
@jackturky instead of
public int compare(String s1, String s2) {
int c = s2.length() - s1.length();
if (c == 0)
c = s1.compareToIgnoreCase(s2);
return c;
}
why not write like (this of course checking null and empty string)
public int compare(String s1, String s2) {
return s1.compareToIgnoreCase(s2);
}
Author by
recoInrelax
Updated on July 09, 2022Comments
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recoInrelax almost 2 years
I have this HashMap:
HashMap<String, Integer> m
which basically stores any word (String) and its frequency (integer). The following code is ordering the HashMap by value:
public static Map<String, Integer> sortByValue(Map<String, Integer> map) { List<Map.Entry<String, Integer>> list = new LinkedList<Map.Entry<String, Integer>>(map.entrySet()); Collections.sort(list, new Comparator<Map.Entry<String, Integer>>() { public int compare(Map.Entry<String, Integer> m1, Map.Entry<String, Integer> m2) { return (m2.getValue()).compareTo(m1.getValue()); } }); Map<String, Integer> result = new LinkedHashMap<String, Integer>(); for (Map.Entry<String, Integer> entry : list) { result.put(entry.getKey(), entry.getValue()); } return result; }
Now the scenario has changed and i have this:
HashMap<String, doc>; class doc{ integer freq; HashMap<String, Double>; }
How can i sort this HashMap by value, following the same approach as sortByValue?
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Ian Campbell about 9 yearsEr, except that's not a HashMap though..