Java Utililty Methods Array to Map

List of utility methods to do Array to Map

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Array to Map

Description

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

Method

HashMap arrayToMap(int[] array)
array To Map

HashMap<Integer, Integer> map = new HashMap<Integer, Integer>();
for (int i = 0; i < array.length; i++) {
 map.put(i + 1, array[i]);
return map;

Map toMap(K[] keys, V[] values)
to Map

HashMap<K, V> map = new HashMap<K, V>();
if (keys != null) {
 for (int i = 0; i < keys.length; i++) {
 map.put(keys[i], values != null ? (i < values.length ? values[i] : null) : null);
return map;

Map toMap(K[] keys, V[] values)
Creates a mutable map out of two arrays with keys and values.

int keysSize = (keys != null) ? keys.length : 0;
int valuesSize = (values != null) ? values.length : 0;
if (keysSize == 0 && valuesSize == 0) {
 return new HashMap<>();
if (keysSize != valuesSize) {
 throw new IllegalArgumentException("The number of keys doesn't match the number of values.");
Map<K, V> map = new HashMap<>();
for (int i = 0; i < keysSize; i++) {
 map.put(keys[i], values[i]);
return map;

Map toMap(String... args)
Transforms the given array into a key-value map using the following rules

keys start with a dash (-) e.g.

Map<String, Object> rv = new HashMap<>();
for (int i = 0; i < args.length; i++) {
 if (args[i].startsWith("-")) { 
 List<String> l = new ArrayList<>();
 String key = args[i].substring(1);
 if (i + 1 < args.length && !args[i + 1].startsWith("-")) { 
 do {
 l.add(args[++i]);
...

Map toMap(String... keysAndValues)
to Map

Map<String, String> ret = new HashMap<String, String>();
if (keysAndValues != null) {
 for (int i = 0; i < keysAndValues.length; i += 2) {
 ret.put(keysAndValues[i], keysAndValues[i + 1]);
return ret;

Map toMap(String[] keyNames, T[] values)
to Map

if (values != null && keyNames != null && values.length >= keyNames.length) {
 Map<String, T> map = new HashMap<String, T>(keyNames.length);
 for (int i = 0; i < keyNames.length; i++) {
 map.put(keyNames[i], values[i]);
 return map;
} else {
 return new HashMap<String, T>(0);
...

Map toMap(String[] keys)
Convert array of strings to string→index map.

Map<String, Integer> m = new HashMap<String, Integer>();
for (int i = 0; i < keys.length; i++) {
 m.put(keys[i], i);
return m;

Map toMap(String[]... wordMappings)
to Map

Map<String, String> mappings = new HashMap<String, String>();
for (int i = 0; i < wordMappings.length; i++) {
 String singular = wordMappings[i][0];
 String plural = wordMappings[i][1];
 mappings.put(singular, plural);
return mappings;

Map toMap(String[][] checksumsArray)
to Map

Map<String, String> checksums = new HashMap<String, String>();
for (String[] checksumPair : checksumsArray) {
 checksums.put(checksumPair[0], checksumPair[1]);
return Collections.unmodifiableMap(checksums);

Map toMap(String[][] strings)
Create a map from an array of string arrays as follows:

For {{key1, value1}, {key2, value2}, ...}, create a map of the keys to values.

final Map<String, String> result = new HashMap<String, String>();
for (String[] array : strings) {
 for (int i = 0; i < array.length - 1; i += 2) {
 result.put(array[i], array[i + 1]);
return result;