Over a million developers have joined DZone.
Platinum Partner

Sorting a HashMap By Values Without Losing Duplicates

· Java Zone

Learn more about Kotlin, a new programming language designed to solve problems that software developers face every day brought to you in partnership with JetBrains.

The below method sorts a HashMap by values without removing duplicates. It works for <String,String> but it can be modified accordingly for other types:

private LinkedHashMap sortMapByValuesWithDuplicates(Map passedMap) {
        List mapKeys = new ArrayList(passedMap.keySet());
        List mapValues = new ArrayList(passedMap.values());
        Collections.sort(mapValues);
        Collections.sort(mapKeys);

        LinkedHashMap sortedMap = new LinkedHashMap();

        Iterator valueIt = mapValues.iterator();
        while (valueIt.hasNext()) {
            Object val = valueIt.next();
            Iterator keyIt = mapKeys.iterator();

            while (keyIt.hasNext()) {
                Object key = keyIt.next();
                String comp1 = passedMap.get(key).toString();
                String comp2 = val.toString();

                if (comp1.equals(comp2)) {
                    passedMap.remove(key);
                    mapKeys.remove(key);
                    sortedMap.put((String) key, (String) val);
                    break;
                }
            }
        }
        return sortedMap;
    }

From http://e-blog-java.blogspot.com/2011/12/sorting-hashmap-by-values-without.html

The Java Zone is brought to you in partnership with JetBrains.  Discover how powerful static code analysis and ergonomic design make development not only productive but also an enjoyable experience.

Topics:

{{ parent.title || parent.header.title}}

{{ parent.tldr }}

{{ parent.urlSource.name }}