Return method for single key in MutilMap

Question

public static String getCTScanSite(String val) {
    Multimap<String, String> map = HashMultimap.create();

    map.put("07", "069");
    map.put("01", "073");
    map.put("04", "085");
    map.put("01", "086");
    map.put("96", "099");
    map.put("112", "100");
    map.put("01", "101");
    map.put("109", "102");
    map.put("106", "103");
    map.put("119", "104");

    return map.toString();
}

What method that I need to use in order to return String val? I used Multimap because I have multiple key. As for now my output would return all key. But I need only String val(passing variable).

"ctScanSite": "{01=[073, 086, 101], 04=[085], 05=[112], 07=[069], ...}"

Thank you

my expected output should return single key:

 "ctScanSite": "01",

Do you mean that you want to return a key whose value is the same as ```val```, or you just want to ```return val```? — zhh, Oct 27 '18 at 13:08
What if multiple keys meet the condition? Will you output all the keys or just a random key? — zhh, Oct 27 '18 at 13:17
Have a look at [is-there-a-way-to-get-all-keys-from-a-value-in-a-multimap](https://stackoverflow.com/questions/15031903/is-there-a-way-to-get-all-keys-from-a-value-in-a-multimap) — zhh, Oct 27 '18 at 13:20
Possible duplicate of [Is there a way to get all keys from a value in a multimap?](https://stackoverflow.com/questions/15031903/is-there-a-way-to-get-all-keys-from-a-value-in-a-multimap) — UninformedUser, Oct 27 '18 at 13:32
previously I used **return map.inverse().get(val);** in BiMap. Since I have multiple same key for different value , I need to used Multimap. my problem is I don't know what method to return same as I used in BiMap — HydrogenUranium, Oct 27 '18 at 13:36

score 0 · Accepted Answer · answered Oct 27 '18 at 14:02

You can use invertFrom of Multimaps and invert your map, then get the keys from the input value using the invertedMap. Refer below:

public static String getCTScanSite(String val) {
    Multimap<String, String> map = HashMultimap.create();

    map.put("07", "069");
    map.put("01", "073");
    map.put("04", "085");
    map.put("01", "086");
    map.put("96", "099");
    map.put("112", "100");
    map.put("01", "101");
    map.put("109", "102");
    map.put("106", "103");
    map.put("119", "104");
    Multimap<String, String> invertedMap = Multimaps.invertFrom(map, ArrayListMultimap.<String, String>create());
    return invertedMap.get(val);
}

Return method for single key in MutilMap

1 Answers1