Question

I have an array of Linq objects of type Link that contains values as following:

new Link {SourceId = 1, TargetId=22223}
new Link {SourceId = 1, TargetId=2221223}
new Link {SourceId = 1, TargetId=222}
new Link {SourceId = 2, TargetId=26556}
new Link {SourceId = 2, TargetId=264}
new Link {SourceId = 2, TargetId=262}
new Link {SourceId = 2, TargetId=29}

class Link
{
    public int SourceId { get; set; }
    public int TargetId { get; set; }
}

I need a LINQ statement to output a dictionary Dictionary<int, List<int>> that contains following:

the distinct SourceId as key and List of TargetId associated with that key as the value.

Many thanks.

Answer 1

var dic = links.GroupBy(x=>x.SourceID)
               .ToDictionary(x=> x.Key, x => x.Select(y=>y.TargetId).ToList());