Tutorial by Examples

var numbers = new[] {1,2,3,4}; var minNumber = numbers.Min(); Console.WriteLine(minNumber); //1 var cities = new[] { new {Population = 1000}, new {Population = 2500}, new {Population = 4000} }; var minPopulation = cities.Min(c => c.Population); Console.WriteLine(minPopu...

var numbers = new[] {1,2,3,4}; var averageNumber = numbers.Average(); Console.WriteLine(averageNumber); // 2,5 This method calculates the average of enumerable of numbers. var cities = new[] { new {Population = 1000}, new {Population = 2000}, new {Population = 4000} }; v...

.NET4.0 var tens = new[] {10,20,30,40,50}; var units = new[] {1,2,3,4,5}; var sums = tens.Zip(units, (first, second) => first + second); Console.WriteLine(string.Join(",", sums)); //11,22,33,44,55

var numbers = new[] {1, 1, 2, 2, 3, 3, 4, 4, 5, 5}; var distinctNumbers = numbers.Distinct(); Console.WriteLine(string.Join(",", distinctNumbers)); //1,2,3,4,5

var persons = new[] { new { Name="Fizz", Job="Developer"}, new { Name="Buzz", Job="Developer"}, new { Name="Foo", Job="Astronaut"}, new { Name="Bar", Job="Astronaut"}, }; var groupedByJob = person...

Returns a new dictionary from the source IEnumerable using the provided keySelector function to determine keys. Will throw an ArgumentException if keySelector is not injective(returns a unique value for each member of the source collection.) There are overloads which allow one to specify the value t...

var numbers1to5 = new[] {1,2,3,4,5}; var numbers4to8 = new[] {4,5,6,7,8}; var numbers1to8 = numbers1to5.Union(numbers4to8); Console.WriteLine(string.Join(",", numbers1to8)); //1,2,3,4,5,6,7,8 Note that duplicates are removed from the result. If this is undesirable, use Concat ...

var numbers = new[] {1,2,3,4,5,6,7,8,9,10}; var someNumbers = numbers.Where(n => n < 6); Console.WriteLine(someNumbers.GetType().Name); //WhereArrayIterator`1 var someNumbersArray = someNumbers.ToArray(); Console.WriteLine(someNumbersArray.GetType().Name); //Int32[]

var numbers = new[] {1,2,3,4,5,6,7,8,9,10}; var someNumbers = numbers.Where(n => n < 6); Console.WriteLine(someNumbers.GetType().Name); //WhereArrayIterator`1 var someNumbersList = someNumbers.ToList(); Console.WriteLine( someNumbersList.GetType().Name + " - " + ...

IEnumerable<int> numbers = new[] {1,2,3,4,5,6,7,8,9,10}; var numbersCount = numbers.Count(); Console.WriteLine(numbersCount); //10 var evenNumbersCount = numbers.Count(n => (n & 1) == 0); Console.WriteLine(evenNumbersCount); //5

var names = new[] {"Foo","Bar","Fizz","Buzz"}; var thirdName = names.ElementAt(2); Console.WriteLine(thirdName); //Fizz //The following throws ArgumentOutOfRangeException var minusOnethName = names.ElementAt(-1); var fifthName = names.ElementAt(4); ...

var names = new[] {"Foo","Bar","Fizz","Buzz"}; var thirdName = names.ElementAtOrDefault(2); Console.WriteLine(thirdName); //Fizz var minusOnethName = names.ElementAtOrDefault(-1); Console.WriteLine(minusOnethName); //null var fifthName = names.Eleme...

var numbers = new[] {2,4,6,8,1,3,5,7}; var oddNumbers = numbers.SkipWhile(n => (n & 1) == 0); Console.WriteLine(string.Join(",", oddNumbers.ToArray())); //1,3,5,7

var numbers = new[] {2,4,6,1,3,5,7,8}; var evenNumbers = numbers.TakeWhile(n => (n & 1) == 0); Console.WriteLine(string.Join(",", evenNumbers.ToArray())); //2,4,6

var numbers = new[] {2,4,6,8,1,3,5,7}; var numbersOrDefault = numbers.DefaultIfEmpty(); Console.WriteLine(numbers.SequenceEqual(numbersOrDefault)); //True var noNumbers = new int[0]; var noNumbersOrDefault = noNumbers.DefaultIfEmpty(); Console.WriteLine(noNumbersOrDefault.Count()); //1 C...

Generating a new object in each step: var elements = new[] {1,2,3,4,5}; var commaSeparatedElements = elements.Aggregate( seed: "", func: (aggregate, element) => $"{aggregate}{element},"); Console.WriteLine(commaSeparatedElements); //1,2,3,4,5, Using th...

var persons = new[] { new { Name="Fizz", Job="Developer"}, new { Name="Buzz", Job="Developer"}, new { Name="Foo", Job="Astronaut"}, new { Name="Bar", Job="Astronaut"}, }; var groupedByJob = person...

class Developer { public int Id { get; set; } public string Name { get; set; } } class Project { public int DeveloperId { get; set; } public string Name { get; set; } } var developers = new[] { new Developer { Id = 1, Name = "Foobuzz" ...

class Developer { public int Id { get; set; } public string Name { get; set; } } class Project { public int DeveloperId { get; set; } public string Name { get; set; } } var developers = new[] { new Developer { Id = 1, Name = "Foobuzz" ...

The as keyword is an operator similar to a cast. If a cast is not possible, using as produces null rather than resulting in an InvalidCastException. expression as type is equivalent to expression is type ? (type)expression : (type)null with the caveat that as is only valid on reference conversions,...