根据Java中的键比较两个不同哈希图的值

Question

I have two different hashmaps. Now I need to compare the hashmaps based on their keys.Like,

HashMap1:
Key: BOF   Value: SAPF,754
Key: BOM   Value: SAPM,456
Key: BOL   Value: SAPL,987


HashMap2:
Key: LOF   Value: YTR,654
Key: BOL   Value: UHG,732

Now I want to compare all those entries in the hashmaps whose 'key's are same and return the difference between the second index of 'values' String[]

Like here it should return: Key: BOL Value: SAPL,255

(as 987-732=255)

How to do it?

Answer 1

map.keySet() will return set of keys in map. Then you have to get value with this key from both map and find the difference.

Map<String, String[]> mp1 = //
Map<String, String[]> mp2 = //
Map<String, List<String>> res = new HashMap<>();
for (String key : mp1.keySet()) {
    int val1 = Integer.valueOf(mp1.get(key)[1]);
    int val2 = Integer.valueOf(mp2.get(key)[1]);
    List<String> resVal = new ArrayList<>();
    resVal.add(mp1.get(key)[0]);
    resVal.add(String.valueOf(val1-val2));
    res.put(key, resVal);
}
return res;

One more thing, you have check for existence. Otherwise you will get NullPointerException