use of Tuple concepts in c#

Question

Why we are using Tuple concepts instead of Dictionary or list?

Vulpes · Answer

Tuples are similar to anonymous types and the latter are superior in one respect because you can give their items names: var person = new{Age = 30 Name = Fred}; Console.WriteLine({0} is aged {1} person.Name person.Age); The corresponding Tuple code is less self-documenting: var person = Tuple.Create(30 Fred); Console.WriteLine({0} is aged {1} person.Item2 person.Item1); However anonymous types suffer from the following drawbacks: 1. They can't be used as return types of methods or properties. 2. They can't be used as method parameter types. 3. They can't be used as field types of classes or structs. Tuples don't suffer from any of these problems and so were worth introducing on those grounds alone. Although a Dictionary can be used to represent a Tuple with two members (or a List to represent a Tuple with any number of members) it's a heavyweight solution to a lightweight problem because these objects are complex internally. On the face of it a KeyValuePair (which is used internally by a Dictionary) should be a viable alternative to a two item tuple but in practice is less performant.

Dhirendra Misra · Answer

Hello A Tuple has many items. Each item can have any type. The Tuple class provides a unified syntax for creating objects with typed fields. Once created the fields in the Tuple cannot be mutated. This makes the Tuple similar to a value type. An example of a tuple is a data structure with three elements (known as a 3-tuple or triple) that is used to store an identifier such as a person's name in the first element a year in the second element and the person's income for that year in the third element. The .NET Framework directly supports tuples with one to seven elements. In addition you can create tuples of eight or more elements by nesting tuple objects in the Rest property of a Tuple object. Tuples are commonly used in four ways: A common use might be to avoid creating classes/structs that only contains a few fields as 2 or 3. To represent a single set of data. For example a tuple can represent a database record and its components can represent individual fields of the record. To provide easy access to and manipulation of a data set. To return multiple values from a method without using out parameters (in C#) or ByRef parameters (in Visual Basic) and avoid passing N out params . To pass multiple values to a method through a single parameter. For example the Thread.Start(Object) method has a single parameter that lets you supply one value to the method that the thread executes at startup time. If you supply a Tuple object as the method argument you can supply the thread's startup routine with three items of data. Examples to create tuple: // Create a 7-tuple. var population = new Tuple string  int  int  int  int  int  int >( New York  7891957 7781984 7894862 7071639 7322564 8008278); // Display the first and last elements. Console.WriteLine( Population of {0} in 2000: {1:N0}  population.Item1 population.Item7); Using Create Method: // Create a 7-tuple. var population = Tuple.Create( New York  7891957 7781984 7894862 7071639 7322564 8008278); // Display the first and last elements. Console.WriteLine( Population of {0} in 2000: {1:N0}  population.Item1 population.Item7); Performance compared with keyValuePair: http://www.dotnetperls.com/tuple-keyvaluepair