Range grouping using linq

Question

How can we use group ranges for equal or large?

var data = new[] { new { Id = 0, Price = 2 }, new { Id = 1, Price = 10 }, new { Id = 2, Price = 30 }, new { Id = 3, Price = 50 }, new { Id = 4, Price = 120 }, new { Id = 5, Price = 200 }, new { Id = 6, Price = 1024 }, }; var ranges = new[] { 10, 50, 100, 500 }; var grouped = data.GroupBy( x => ranges.FirstOrDefault( r => r > x.Price ) ); grouped ouput is price 10-50 -> 3 price 50-100 -> 1 price 100-500 -> 2 

The required output is grouped into equal or greater than the range used.

 price >= 10 -> 6 price >= 50 -> 4 price >= 100 -> 3 price >= 500 -> 1 

Answer 1

 var grouped = ranges.Select(r => new { Price = r, Count = data.Where(x => x.Price >= r).Count() }); 

And one more option (if you have huge data, then grouping is better than listing all the data for each price group):

 var priceGroups = data.GroupBy(x => ranges.FirstOrDefault(r => r > x.Price)) .Select(g => new { Price = g.Key, Count = g.Count() }) .ToList(); var grouped = ranges.Select(r => new { Price = r, Count = priceGroups.Where(g => g.Price > r || g.Price == 0).Sum(g => g.Count) }); 

Answer 2

Grouping sections of the source, each element is assigned to one group.

You have a good start:

 var data = new[] { new { Id = 0, Price = 2 }, new { Id = 1, Price = 10 }, new { Id = 2, Price = 30 }, new { Id = 3, Price = 50 }, new { Id = 4, Price = 120 }, new { Id = 5, Price = 200 }, new { Id = 6, Price = 1024 }, }; var ranges = new[] { 10, 50, 100, 500 }; var grouped = data.GroupBy( x => ranges.FirstOrDefault( r => r <= x.Price ) ); 

Follow him:

 int soFar = 0; Dictionary<int, int> counts = grouped.ToDictionary(g => g.Key, g => g.Count()); foreach(int key in counts.Keys.OrderByDescending(i => i)) { soFar += counts[key]; counts[key] = soFar; } 

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Or if you want to do this in a single linq expression:

 int soFar = 0; var grouped = data .GroupBy( x => ranges.FirstOrDefault( r => r <= x.Price ) ) .OrderByDescending(g => g.Key) .Select(g => { soFar += g.Count(); return new Tuple<int, int>(g.Key, soFar) });