Find Min Key by Value if Map contains key(SubString here ) for Map<String, Double>

Question

I have a HashMap with Strings as keys and values. And I have a String. Now I want to do something like that:

Example

Map<String, Double> storeDistance = new HashMap<String, Double>();
map.put("10-ABCD-01", 15.75);
map.put("10-XYZ-05", 12.13);
map.put("10-ABCD-06", 11.06);
map.put("10-ABCD-04", 10.76);
map.put("10-XYZ-03", 07.62);

Now I Want to find Store ABCD with minimum distance out of all. Here in the case I want to get Store Value as "10-ABCD-04" cause it has minimum distance out of all Keys with Substring ABCD.

I was trying something like below, but it was not working. So any Suggestion here.

storeDistance.keySet().stream()
                           .filter(key -> key.contains("ABCD")).map(storeDistance::get).collect(Collectors.toMap(Map.Entry::getKey, Map.Entry::getValue, Math::min));

        
            

Answer 1

Use min(Comparator) on the stream of your key set to get an optional key

String result = storeDistance.keySet().stream().filter(key -> key.contains("ABCD"))
       .min(Comparator.comparingDouble(storeDistance::get)).get();