LINQ – Examples

In diesem Beitrag möchte ich Anregungen geben, wie man effektiv mit LINQ-Queries arbeiten kann.

public static string[] CSV_CONTENT =new string[]
{
    "Datum;Name;Distanz",
    "1.1.2015;Ca;200",
    "2.1.2015;We;300",
    "2.1.2015;We;100",
    "2.1.2015;Ca;150",
    "12.2.2015;Ca;50",
};
static void ParseCSV()
{
    // Skip Header:
    IEnumerable<string> rowsWithContent = CSV_CONTENT.Skip(1);
    // Split rows into columns:
    IEnumerablee<string[]> data = rowsWithContent.Select(x => x.Split(';'));
    // Filter all wrong rows:
    IEnumerablee<string[]> correctData = data.Where(row => row.Length == 3 && row.All(cell=>!string.IsNullOrEmpty(cell)));
    //Generate Datastructure:
    var richData=correctData.Select(row=>
        new {
            DatePoint=DateTime.Parse(row[0]),
            Name=row[1],
            Distance=uint.Parse(row[2])
        });
    // Read out data:
    Console.WriteLine("Total Minimum: {0} | Total Maximum: {1}", richData.Min(x => x.Distance), richData.Max(x => x.Distance));
    var personResults = richData.GroupBy(x =>? x.Name);
    foreach (var item in personResults)
    {
        Console.WriteLine("Result of: " + item.Key);
        Console.WriteLine("   First entry: " + item.Min(x => x.DatePoint));
        Console.WriteLine("   Last entry: " + item.Max(x => x.DatePoint));
        Console.WriteLine("   Total distance: " + item.Sum(x => x.Distance));
    }
}