I need to write a method that will convert the mass into Map
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1You have your expected and actual reversed.matt– matt2022-01-09 13:46:20 +00:00Commented Jan 9, 2022 at 13:46
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3 Answers
i is an array, so when you put it as the key of your Map, you get a Map<Object[],Object>.
You don't need a nested loop:
public Map<Character, Integer> arrayToMap(Object[][] args) {
Map<Character, Integer> map = new LinkedHashMap<>();
for (Object[] i : args) {
map.put((Character) i[0], (Integer) i[1]);
}
return map;
}
Each inner array of your 2D array should become a pair of key and value in the output Map.
Comments
Use Stream API with Callectors.toMap method:
public static Map<Character, Integer> arrayToMap(Object[][] arr) {
return Arrays.stream(arr)
.collect(Collectors.toMap(o -> (Character)o[0],
o -> (Integer)o[1],
(oldV, newV) -> newV,
LinkedHashMap::new
));
}
Comments
2D array in Java is an array of arrays; i.e. in your example, you have a 1D array of 1D arrays with exactly 2 elements [char, int]
public static void main(String[] args) {
Object[][] arr = {
{ '1', 1 }, { ' ', 5 }, { '2', 2 }, { '3', 3 },
{ '4', 4 }, { '5', 5 }, { '6', 6 } };
Map<Character, Integer> map = arrayToMap(arr);
System.out.println(map);
}
public static Map<Character, Integer> arrayToMap(Object[][] arr) {
Map<Character, Integer> map = new HashMap<>();
for (int i = 0; i < arr.length; i++)
map.put((char)arr[i][0], (int)arr[i][1]);
return map;
}
