How do I convert a Dictionary to a Lookup?
.net, c#, dictionary, list, lookup
Solution
You could use:
var lookup = dictionary.SelectMany(p => p.Value
.Select(x => new { p.Key, Value = x}))
.ToLookup(pair => pair.Key, pair => pair.Value);
(You could use `KeyValuePair` instead of an anonymous type - I mostly didn't for formatting reasons.)
It's pretty ugly, but it would work. Can you replace whatever code created the dictionary to start with though? That would probably be cleaner.
Problem
I have a Dictionary that has a signature: `Dictionary<int, List<string>>`. I'd like to convert it to a Lookup with a signature: `Lookup<int, string>`. I tried: ``` Lookup<int, string> loginGroups = mapADToRole.ToLookup(ad => ad.Value, ad => ad.Key); ``` But that is not working so well.