using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Threading.Tasks; using static System.Console; //Time limit will be reached before finishing the whole program namespace Cars_LINQ_Example2 { delegate void Log(string s, params object[] args); class DOGGO { public static Log log = WriteLine; static void Main(string[] args) { string[] CarBrands = { "Mercedez", "Spada", "Lotus", "Toyota", "Honda", "Hyunday", "Corvette", "KIA", "Chevrolet", "Tramontana", "Lamborghini", "Ferrari", "Pontiac", "Cadillac" }; log("=====NONDEFERRED OPERATORS====="); log("\n----------TOARRAY"); List Names = new List(); Names.Add("Sergey"); Names.Add("Aleksandr"); Names.Add("Maria"); Names.Add("John"); Names.Add("Bruce"); Names.Add("Emily"); log($"Names type = {Names.GetType().ToString()}"); var newNames = Names.ToArray(); log($"newNames type = {newNames.GetType().ToString()}"); log("\n----------TOLIST"); log($"CarBrands type = {CarBrands.GetType().ToString()}"); var newCarBrands = CarBrands.ToList(); log($"newCarBrands type = {newCarBrands.GetType().ToString()}"); log("\n----------TODICTIONARY"); log("--first version"); Dictionary outDict = CarBrands.ToDictionary(s => Array.IndexOf(CarBrands, s)); foreach (var element in outDict) { log($"Key = {element.Key} Value = {element.Value}"); } log("--second version"); IntComparer comp = new IntComparer(); outDict = CarBrands.ToDictionary(s => Array.IndexOf(CarBrands, s),comp); foreach (var element in outDict) { log($"Key = {element.Key} Value = {element.Value}"); } log("--third version"); Dictionary dict = CarBrands.ToDictionary(s => Array.IndexOf(CarBrands, s),el => el.Length); foreach (var element in dict) { log($"Key = {element.Key} Value = {element.Value}"); } log("--fourth version"); dict = CarBrands.ToDictionary(s => Array.IndexOf(CarBrands, s), el => el.Length,comp); foreach (var element in dict) { log($"Key = {element.Key} Value = {element.Value}"); } log("\n----------TOLOOKUP"); log("--first version"); ILookup outLook = CarBrands.ToLookup(s => Array.IndexOf(CarBrands, s)); IEnumerable car = outLook[4]; foreach (var str in car) { log($"Fifth car is = {str}"); } log("--second version"); outLook = CarBrands.ToLookup(s => Array.IndexOf(CarBrands, s),comp); car = outLook[3]; foreach (var str in car) { log($"Fourth car is = {str}"); } log("--third version"); ILookup outLook2 = CarBrands.ToLookup(s => Array.IndexOf(CarBrands, s),el => el.Length); IEnumerable carl = outLook2[4]; foreach (var i in carl) { log($"Fifth car lengh is = {i}"); } log("--fourth version"); outLook2 = CarBrands.ToLookup(s => Array.IndexOf(CarBrands, s), el => el.Length,comp); carl = outLook2[3]; foreach (var i in carl) { log($"Fourth car lengh is = {i}"); } log("\n----------SEQUENCEEQUAL"); log("--first version"); int[] seq1 = { 0, 5, 25 }; int[] seq2 = { 0, 5, 25 }; string[] Cars2 = { "Ford", "Acura"}; WriteLine(CarBrands.SequenceEqual(Cars2)); WriteLine(seq1.SequenceEqual(seq2)); log("--second version"); WriteLine(seq1.SequenceEqual(seq2,comp)); log("\n----------FIRST"); log("--first version"); log(CarBrands.First()); log("--second version"); log(CarBrands.First(s=>s.StartsWith("Po"))); log("\n----------FIRSTORDEFAULT"); log("--first version"); log(CarBrands.FirstOrDefault()); string [] seqstr = {}; try { log(seqstr.First()); } catch (System.InvalidOperationException e) { log("Fisrt operator on empty sequence raises exception"); } if(String.IsNullOrEmpty(seqstr.FirstOrDefault())) { log("We got default value of string = null"); } log("--second version"); log(CarBrands.FirstOrDefault(s => s.StartsWith("La"))); log("\n----------LAST"); log("--first version"); log(CarBrands.Last()); log("--second version"); log(CarBrands.Last(s => s.StartsWith("L"))); log("\n----------LASTORDEFAULT"); log("--first version"); log(CarBrands.LastOrDefault()); try { log(seqstr.Last()); } catch (System.InvalidOperationException e) { log("Last operator on empty sequence raises exception"); } if (String.IsNullOrEmpty(seqstr.LastOrDefault())) { log("We got default value of string = null"); } log("--second version"); log(CarBrands.LastOrDefault(s => s.StartsWith("L"))); log("\n----------SINGLE"); log("--first version"); string[] singleElementSequence = { "single one"}; log(singleElementSequence.Single()); log("--second version"); log(CarBrands.Single(s => s.StartsWith("Mer"))); log("\n----------SINGLEORDEFAULT"); log("--first version"); string[] singleElementSequence2 = {}; if (String.IsNullOrEmpty(singleElementSequence2.SingleOrDefault())) { log("We got default value of string = null"); } log("--second version"); if (String.IsNullOrEmpty(singleElementSequence2.SingleOrDefault(s=> s.StartsWith("strange string")))) { log("We again got default value of string = null"); } log("\n----------ELEMENTAT"); log($"Element at position 2 is: {CarBrands.ElementAt(2)}"); log("\n----------ELEMENTATORDEFAULT"); if (String.IsNullOrEmpty(CarBrands.ElementAtOrDefault(-1))) { log("We got default value of string = null"); } log("\n----------ANY"); log("--first version"); string[] emptySequence = { }; if (!emptySequence.Any()) { log("Input sequence is empty"); } log($"Has CarBrands any elements? : {CarBrands.Any()}"); log("--second version"); log($"Does car brands has something that starts with B: {CarBrands.Any(s=> s.StartsWith("B"))}"); log("\n----------ALL"); log($"Do all elements of CarBrands has more than 3 symbols: {CarBrands.All(s => {if(s.Length>3)return true;return false;})}"); log($"Do all elements of CarBrands has more than 2 symbols: {CarBrands.All(s => { if (s.Length > 2)return true; return false; })}"); log("\n----------Contains"); log("--first version"); log($"Does CarBrands contain BMW: {CarBrands.Contains("BMW")}"); int[] ints = { 0, 1, 2, 3, 4, 5 }; log("--second version"); log($"Does ints contain 5 with comparer: {ints.Contains(5,comp)}"); log("\n----------COUNT"); log("--first version"); log($"CarBrands count: {CarBrands.Count()}"); log("--second version"); log($"CarBrands count where length > 4: {CarBrands.Count(s=> s.Length > 4)}"); log("\n----------LONGCOUNT"); log("--first version"); log($"CarBrands count: {CarBrands.LongCount()}"); log("--second version"); log($"CarBrands count where length > 5: {CarBrands.LongCount(s => s.Length > 5)}"); log("\n-----------------SUM"); double[] doubles = { 0.1, 1.2, 2.3, 3.5, 4.6, 5.3 }; log("--first version"); log($"Sum of doubles is: {doubles.Sum()}"); log("--second version"); log($"Sum of chars in CarBrands is: {CarBrands.Sum(s=> s.Length)}"); log("\n----------MIN"); log("--first version"); log($"Min of doubles is: {doubles.Min()}"); log("--second version"); log($"Min in CarBrands: {CarBrands.Min()}"); log("--third version"); log($"Min in CarBrands by length is: {CarBrands.Min(s => s.Length)}"); log("--fourth version"); log($"Min in CarBrands (we imagine this is class and return string value for name from it): {CarBrands.Min(s => s.ToString())}"); log("\n----------MAX"); log("--first version"); log($"Max of doubles is: {doubles.Max()}"); log("--second version"); log($"Max in CarBrands: {CarBrands.Max()}"); log("--third version"); log($"Max in CarBrands by length is: {CarBrands.Max(s => s.Length)}"); log("--fourth version"); log($"Max in CarBrands (we imagine this is class and return string value for name from it): {CarBrands.Max(s => s.ToString())}"); log("\n----------AVERAGE"); log("--first version"); log($"Average of doubles is: {doubles.Average()}"); log("--second version"); log($"Average of lengths in CarBrands is: {CarBrands.Average(s => s.Length)}"); } public class MyStringComparer:IComparer { public int Compare(string first, string second) { if (first.Length > second.Length) return 1; if (first.Length < second.Length) return -1; return 0; } } public class IntComparer : IEqualityComparer { public bool Equals(int x, int y) { return x == y; } public int GetHashCode(int i) { return i; } } } }

LINQ Example #4