Question

Given, for instance:

var a = new List<int>(){ 1 , 2 , 50 };
var b = new List<int>(){ 9 , 7 , 2 };

I need to merge them together to one sorted list, while adding some data indicating their origin (a or b). An output for example would be something like:

mergedList = { {1,false},{2,false},{2,true},{7,true},{9,true},{50,false} }

(true means it comes from a).

Edit start…

mergedList =
{ {1,IsB=false},{2,IsB=false},{2,IsB=true},{7,IsB=true},{9,IsB=true},{50,IsB=false} }

…Edit end

How can I do it with LINQ, preferably in query statement form (from ... select ...) ?

Answer 1

var aItems = from aa in a
             select new {Value = aa, Indicator = true};
var bItems = from bb in b
             select new {Value = bb, Indicator = false};

var result = aItems.Concat(bItems).OrderBy(t => t.Value);

And pure method syntax:

var aItems = a.Select(aa => new {Value = aa, Indicator = true});
var bItems = b.Select(bb => new {Value = bb, Indicator = false});
var result = aItems.Concat(bItems).OrderBy(t => t.Value);