Question

I have a list of Foo. Foo has properties Bar and Lum. Some Foos have identical values for Bar. How can I use lambda/linq to group my Foos by Bar so I can iterate over each grouping’s Lums?

Answer 1

Deeno,

Enjoy:

var foos = new List<Foo> {    new Foo{Bar = 1,Lum = 1},    new Foo{Bar = 1,Lum = 2},    new Foo{Bar = 2,Lum = 3}, };  // Using language integrated queries:  var q = from foo in foos         group foo by foo.Bar into groupedFoos         let lums = from fooGroup in groupedFoos                    select fooGroup.Lum         select new { Bar = groupedFoos.Key, Lums = lums };  // Using lambdas  var q = foos.GroupBy(x => x.Bar).             Select(y => new {Bar = y.Key, Lums = y.Select(z => z.Lum)});   foreach (var group in q) {     Console.WriteLine('Lums for Bar#' + group.Bar);     foreach (var lum in group.Lums)     {         Console.WriteLine(lum);     } } 

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