How to get Map keys by values in Dart?

Question

In Dart language how to get MAP keys by values?

I have a Map like;

{
  \"01\": \"USD\",
  \"17\": \"GBP\",
  \"33\": \"EUR\"
}

And I n

Answer 1

If you will be doing this more than a few times on the same data, you should create an inverse map so that you can perform simple key lookup instead of repeated linear searches. Here's an example of reversing a map (there may be easier ways to do this):

main() {
  var orig = {"01": "USD", "17": "GBP", "33": "EUR"};
  var reversed = Map.fromEntries(orig.entries.map((e) => MapEntry(e.value, e.key)));
  for (var kv in reversed.entries) {
    print(kv);
  }
}

Edit: yes, reversing a map can simply be:

var reversed = orig.map((k, v) => MapEntry(v, k));

Tip of the hat to Joe Conway on gitter. Thanks.