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LINQ, data sampling and transformation

Manual C# · Examples UO

LINQ processes the sequences: Where filters, Select transforms, OrderBy sorts, GroupBy groups, Any/All checks the condition, Count/Sum aggregates. Many operations are executed deferred while the result is enumerated; ToArray and ToList capture the picture.

Simple example (Example.cs)

Save this example separately as Example.cs. Run it independently of the other examples on this page.

Example.cs:

// PROJECT-EXAMPLE
using System.Linq;
int[] values = [1, 2, 3];
var selected = values.Where(value => value > 1);
System.Console.WriteLine(string.Join(",", selected));

Result:

2,3

int[] amounts = [1, 5, 2, 10];
var selected = amounts.Where(value => value >= 5).OrderBy(value => value).ToArray();
UO.Print(string.Join(", ", selected));

var entries = new[]
{
    new { Name = "ore", Amount = 2 },
    new { Name = "wood", Amount = 3 },
    new { Name = "ore", Amount = 4 }
};
var totals = from entry in entries
             group entry by entry.Name into groupValue
             select new { Name = groupValue.Key, Total = groupValue.Sum(value => value.Amount) };
foreach (var total in totals)
{
    UO.Print($"{total.Name}: {total.Total}");
}

First throws an exception if there is no element; FirstOrDefault returns the default value. Re-enumerating a deferred request may again read the changed data, so take a snapshot of the game list carefully.

Official Documentation: LINQ, Data Retrieval and Transformation - Microsoft Learn.