Java Utililty Methods Map Invert

List of utility methods to do Map Invert

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Map Invert

Description

The list of methods to do Map Invert are organized into topic(s).

Method

for (Entry<K, V> entry : m.entrySet()) {
 newMap.put(entry.getValue(), entry.getKey());
return newMap;

Map inverse(Map map)
inverse

Map<V, K> inverse = new HashMap<>(map.size());
for (Entry<K, V> entry : map.entrySet()) {
 if (inverse.put(entry.getValue(), entry.getKey()) != null) {
 throw new IllegalArgumentException(map + " is not a bijection.");
return inverse;

Map inverse(Map map)
Generates a map with the original map's values as keys and its keys as values.

Map<V, K> newMap = new HashMap<>(map.size());
for (Map.Entry<K, V> entry : map.entrySet()) {
 if (newMap.containsKey(entry.getValue())) {
 throw new IllegalArgumentException(
 String.format("There are two keys with the value %s in the map", entry.getValue()));
 newMap.put(entry.getValue(), entry.getKey());
return newMap;

Collection inverseGet(Map map, Object value)
inverse Get

Collection<K> result = new LinkedList<K>();
for (Iterator<Entry<K, V>> it = map.entrySet().iterator(); it.hasNext();) {
 Entry<K, V> name = it.next();
 if (equalsNullOK(value, name.getValue())) {
 result.add(name.getKey());
return result;
...

Map invert(Map map)
Inverts the values of a list.

Map<B, A> map1 = new HashMap<>();
map.forEach((k, v) -> map1.put(v, k));
return map1;

HashMap invert(Map in)
invert

HashMap<V, K> result = new HashMap<V, K>();
for (Map.Entry<K, V> e : in.entrySet()) {
 result.put(e.getValue(), e.getKey());
return result;

Map invert(Map map)
Method to invert a map i.e keys becomes values and vice versa

if (map != null) {
 Map<V, K> returnValue = new HashMap<>();
 for (Entry<K, V> entry : map.entrySet()) {
 if (entry != null) {
 returnValue.put(entry.getValue(), entry.getKey());
 return returnValue;
...

List

invert(Map map, String prefix)

List<Map<String, Object>> list = new ArrayList<>();
for (Map.Entry<String, Object> entry : map.entrySet()) {
 if (entry.getKey().startsWith(prefix)) {
 String key = entry.getKey().substring(prefix.length());
 if (Iterable.class.isAssignableFrom(entry.getValue().getClass())) {
 int i = 0;
 for (Object e : ((Iterable) entry.getValue())) {
 for (int j = list.size(); j <= i; j++) {
...

Map invert(Map map)
invert

Map<U, T> inversion = new HashMap<U, T>();
for (Entry<T, U> e : map.entrySet()) {
 if (inversion.put(e.getValue(), e.getKey()) != null) {
 throw new IllegalArgumentException("Inversion is not a valid map");
return unmodifiableMap(inversion);

Map invertedMapFrom(Map source)
Returns a map based on the source but with the key & values swapped.

Map<V, K> map = new HashMap<>(source.size());
for (Map.Entry<K, V> entry : source.entrySet()) {
 map.put(entry.getValue(), entry.getKey());
return map;