LinQ Queires

List of LinQ queries

1. Aggregate:



1 2	var errors = Error.Aggregate("Error occured: ", (current, error) => current + $"Code - {error.Code}, Detail - {error.Text}; ");

2. Select Many:



IEnumerable data; if (data.SelectMany(s => s.Category) .Where(si => si.SubCategory.Any(si => si.Selected)).Select(ti => ti.SubCategoryId) .Distinct().Count() > 1) { // }

3. For Each:



Parallel.ForEach(Categories,
              Category =>
              {
                  Logger.Log(
                     Category.Id);
              };

            parameters.ToList().ForEach(x => command.Parameters.Add(x));

foreach (var node in xnode.Descendants("node1"))
 {
                node.Nodes().ToList().ForEach(n => n.Remove());
 }

4. Order By:



data.OrderBy(s => s.date).ToArray();

5. Join:



$"{Error} (Description: {string.Join(", ", ErrorCodes?.Select(e => e.ToString()))}";

var amount = from a in price.LineItems
             join b in discount.LineItems on a.Id equals b.Id
             where (a.amount ?? 0)) > b.amount)
             select new { a, b };

6. Select New:



 return (from cat in result.Cast<dynamic>()
                    group cat by cat.Id
                           into bycat
                    let subcat =
                        from region in bycat
                        group region by region.Region
                            into byRegion
                        let subsubcat =
                                    from code in byRegion
                                group code by code.Code
                                        into byCode
                                select (string)byCode.Key
                        select new
                        {
                            Name = (string)byRegion.Key,
                            Codes =
                                        subsubcat.ToList()
                        }
                    select new Cat<string>
                    {
                        Name = byCat.Key,
                        Regions =
                            subcat.ToDictionary(r => r.Name, r => r.Codes,
                                StringComparer.InvariantCultureIgnoreCase)

                    }).ToDictionary(c => c.Name, c => c, StringComparer.InvariantCultureIgnoreCase);
        }

        select new Info((new[]
                {
                    cat.Select(lineItem => lineItem.LineItem).ToList()
                })
                .ToList()
                .ForEach(Infos.Add);

7. Group By:



foreach (var grpCat in items.GroupBy(cat => cat.Id))
            {
            }

8. TakeWhile
   
    foreach (var cat in categories.TakeWhile(esi => categories == null))
     {
     }

9. IEnumerable:




1 2 3 4 5 6 7 8 9 10 11 12 13

using System.Collections.Generic; namespace Web.Models { public static class Class { IEnumerable<CatInfo> data; if (TryExecuteQuery(out data, "GetData", parameters)) { info = data.ToList(); } } }