I have a list of channels like:
List <String> locations = Arrays.asList (“US: 5423”, “US: 6321”, “CA: 1326”, “AU: 5631”);
And I want to convert Map <String, List <String >> like this:
AU = [5631] CA = [1326] US = [5423, 6321]
How can I do that?
You can do it like this:
Card <String, List <String >> locationMap = locations.stream ()
.map (s -> s.split (“:”))
.collect (Collectors.groupingBy (a -> a [0],
Collectors.mapping (a -> a [1], Collectors.toList ()));
A much better approach would be
private static final model DELIMITER = Pattern.compile (“:”);
Card <String, List <String >> locationMap = locations.stream ()
.map (s -> DELIMITER.splitAsStream (s) .toArray (String[] :: new))
.collect (Collectors.groupingBy (a -> a [0],
Collectors.mapping (a -> a [1], Collectors.toList ()));
