Java - add key / value to map within map in 1 line of code?

Question

I have a HashMap 1 that contains 5 keys, all of which have Hashmaps values. I want to add key / value pairs to these sub-Maps.

map1.get(subCategoryMap).put(newKey, newValue); 

My thinking:

map1.get(subCategoryMap);

returns another card. I could split this line into two lines and have:

map2 = map1.get(subCategoryMap);
map2.put(newKey, newValue);

But I would prefer to do it in one step. That's why i try

map1.get(subCategoryMap).put(newKey, newValue); 

This does not work (do not like .put () for the object). Is it possible to access the sub-map and add to it in the same line of code as me, or do I need to split it into two lines?

Answer 1

With generics, you can:

Map<String, Map<String, String>> map1 = ...
map1.get(category).put(subcategory, value);

If the cards are not shared:

Map map1 = ...
((Map)map1.get(category)).put(subcategory, value);

Answer 2

((Map)map1.get(subCategoryMap)).put(newKey, newValue);

Or, use generics:

Map<X, Map<Y,Z>> map1;

...

map1.get(subCategoryMap).put(newKey, newValue);

NullPointerException, map1 subCategoryMap.

Answer 3

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dataHolder.put(category, newKey, newVale);

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Answer 4

Generics, HashMap Object, , :

((HashMap)map1.get(subCategoryMap)).put(newKey, newValue);

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Answer 5

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Answer 6

map1 - Map<OuterKey, Map<InnerKey, MyValue>>, . , , subCategoryMap map1 — NullPointerException.

Answer 7

((HashMap)map1.get(subCategoryMap)).put(newKey, newValue);

, Java 5 Java 6, generic, HashMap

Answer 8

, :

Map<String,Map<String,Integer>> map = new HashMap<String,Map<String,Integer>>();
map.put("Test", new HashMap<String,Integer>());
map.get("Test").put("Some", 1);