Vargars in Java Hashmap

Question

HashMap <String,String... strings> hm = new HashMap<String,String... strings>();

hm.put("Zara", "Pony","Cars", "Magic");
hm.put("John", "Horse","Flying", "Loving");

I want to do this, how do I do this? This does not allow me.

Answer 1

The elipsis ( ...) operator can only be used in method signatures. You can explicitly declare and create arrays:

Map<String, String[]> hm = new HashMap<>();

hm.put("Zara", new String[]{"Pony", "Cars", "Magic"});
hm.put("John", new String[]{"Horse", "Flying", "Loving"});

If you absolutely must use varags, you can bind a call to Map#putyour method:

public static void main(String[] args) {
    Map<String, String[]> hm = new HashMap<>();

    addToMap(hm, "Zara", "Pony", "Cars", "Magic");
    addToMap(hm, "John", "Horse", "Flying", "Loving");
}

private static void addToMap
    (Map<String, String[]> map, String key, String... values) {
    map.put(key, values);
}

Answer 2

Closest you can use the "Map" and create a method for this

public static void addToMap(Map<String, String[]> map, String key, String...values) {
    map.put(key, values);
}

Answer 3

Vararg , . .

, . varargs . List Set.

:

• :

  HashMap <String, String[]> hm = new HashMap<>();
  hm.put("Zara", new String[] {"Pony","Cars", "Magic"});
  hm.put("John", new String[] {"Horse", "Flying", "Loving"});
  

• :

  HashMap <String, List<String>> hm = new HashMap<>();
  hm.put("Zara", new ArrayList<String>());
  hm.get("Zara").add("Pony");
  hm.get("Zara").add("Cars");
  hm.get("Zara").add("Magic");
  hm.put("John", new ArrayList<String>());
  hm.get("John").add("Horse");
  hm.get("John").add("Flying");
  hm.get("John").add("Loving");
  

Answer 4

See this question . Basically you need to do the following:

hm.put("Zara", new String[]{"Pony", "Cars", "Magic"});

Or if you want to declare it separately:

String[] zaraValues = new String[]{"Pony", "Cars", "Magic"};
hm.put("Zara", zaraValues);

Answer 5

You may be looking for the following:

HashMap<String, List<String>> hm = new HashMap<>();
hm.put("Zara", Arrays.asList("Pony", "Cars", "Magic"));
hm.put("John", Arrays.asList("Horse", "Flying", "Loving"));