//with given following methods public static bool IsitOdd(int i) { return ((i & 1) == 1); } public static bool IsitEven(int i) { return ((i & 1) != 1); } //here is the code. int[] numbers = { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20 }; var oddNums = from n in numbers where (IsitOdd(n)) select n; var evenNums = from n in numbers where (IsitEven(n)) select n; // Other Syntax int[] oddNums2 =numbers .Select(n => n ) .Where(P => IsitOdd(P)).ToArray(); int[] evenNums2 = numbers .Select(n => n) .Where(P => IsitEven(P)).ToArray();

Given a class like below.. public class NumbersFilters { public delegate bool AnyFilter(int i); public static int[] GetFilteredInts(int[] ints, AnyFilter filter) { ArrayList aList = new ArrayList(); foreach (int i in ints) { if (filter(i)) { aList.Add(i); } } return ((int[])aList.ToArray(typeof(int))); } } //we have three choices of usage // using named method int[] evenNums1 = NumbersFilters.GetFilteredInts(numbers, IsitEven); // using anonymous method int[] evenNums2 = NumbersFilters.GetFilteredInts(numbers, delegate(int i) { return ((i & 1) != 1); }); // using lambda expression int[] evenNums3 = NumbersFilters.GetFilteredInts(numbers, i => ((i & 1) != 1));

---------------------------------------- //Numbers Less than 10 IEnumerable<int> numsLessThanTen = numbers.Select(i => i) .Where(i => i < 10) .OrderBy(i => i); IEnumerable<int> numsLessThanTen2 = from n in numbers where (n < 10) select n;