How to easily initialize a list of Tuples

Question

I love tuples  They allow you to quickly group relevant information together without having to write a struct or class for it  This is very useful while refactoring very localized code  Initializing a list of them however seems a bit redundant  var tupleList   new List lt Tuple lt int  string gt  gt        Tuple Create  1   quot cow quot         Tuple Create  5   quot chickens quot         Tuple Create  1   quot airplane quot        Isn t there a better way  I would love a solution along the lines of the Dictionary initializer  Dictionary lt int  string gt  students   new Dictionary lt int  string gt            111   quot bleh quot           112   quot bloeh quot           113   quot blah quot        Can t we use a similar syntax

User · Accepted Answer

c  7 0 lets you do this     var tupleList   new List lt  int  string  gt             1   cow           5   chickens           1   airplane          If you don t need a List  but just an array  you can do     var tupleList   new int  string               1   cow           5   chickens           1   airplane          And if you don t like  Item1  and  Item2   you can do     var tupleList   new List lt  int Index  string Name  gt             1   cow           5   chickens           1   airplane          or for an array     var tupleList   new  int Index  string Name               1   cow           5   chickens           1   airplane          which lets you do  tupleList 0  Index and tupleList 0  Name  Framework 4 6 2 and below  You must install System ValueTuple from the Nuget Package Manager   Framework 4 7 and above  It is built into the framework  Do not install System ValueTuple  In fact  remove it and delete it from the bin directory   note  In real life  I wouldn t be able to choose between cow  chickens or airplane  I would be really torn

User · Answer

var colors   new                 new   value   Color White  name    White             new   value   Color Silver  name    Silver             new   value   Color Gray  name    Gray             new   value   Color Black  name    Black             new   value   Color Red  name    Red             new   value   Color Maroon  name    Maroon             new   value   Color Yellow  name    Yellow             new   value   Color Olive  name    Olive             new   value   Color Lime  name    Lime             new   value   Color Green  name    Green             new   value   Color Aqua  name    Aqua             new   value   Color Teal  name    Teal             new   value   Color Blue  name    Blue             new   value   Color Navy  name    Navy             new   value   Color Pink  name    Pink             new   value   Color Fuchsia  name    Fuchsia             new   value   Color Purple  name    Purple               foreach  var color in colors                stackLayout Children Add              new Label                               Text   color name                  TextColor   color value                          FontSize   Device GetNamedSize NamedSize Large  typeof Label          this is a Tuple lt Color  string gt

User · Answer

One technique I think is a little easier and that hasn t been mentioned before here   var asdf   new            Age  1  Name   cow          Age  2  Name   bird     ToList      I think that s a little cleaner than   var asdf   new List lt Tuple lt int  string gt  gt          Age  1  Name   cow          Age  2  Name   bird

User · Answer

Super Duper Old I know but I would add my piece on using Linq and continuation lambdas on methods with using C  7   I try to use named tuples as replacements for DTOs and anonymous projections when reused in a class   Yes for mocking and testing you still need classes but doing things inline and passing around in a class is nice to have this newer option IMHO   You can instantiate them from        Direct Instantiation      var items   new List lt  int Id  string Name  gt     1   Me     2   You             Off of an existing collection  and now you can return well typed tuples similar to how anonymous projections used to be done       public class Hold       public int Id   get  set        public string Name   get  set         In some method or main console app  var holds   new List lt Hold gt    new Hold   Id   1  Name    Me     new Hold   Id   2  Name    You       var anonymousProjections   holds Select x   gt  new   SomeNewId   x Id  SomeNewName   x Name     var namedTuples   holds Select x   gt   TupleId  x Id  TupleName  x Name            Reuse the tuples later with grouping methods or use a method to construct them inline in other logic         Assuming holder class above making  holds  object public  int Id  string Name  ReturnNamedTuple int id  string name    gt   id  name   public static List lt  int Id  string Name  gt  ReturnNamedTuplesFromHolder List lt Hold gt  holds    gt  holds Select x   gt   x Id  x Name   ToList    public static void DoSomethingWithNamedTuplesInput List lt  int id  string name  gt  inputs    gt  inputs ForEach x   gt  Console WriteLine   Doing work with  x id  for  x name       var namedTuples2   holds Select x   gt  ReturnNamedTuple x Id  x Name    var namedTuples3   ReturnNamedTuplesFromHolder holds   DoSomethingWithNamedTuplesInput namedTuples ToList

User · Answer

Old question  but this is what I typically do to make things a bit more readable   Func lt int  string  Tuple lt int  string gt  gt  tc   Tuple Create   var tupleList   new List lt Tuple lt int  string gt  gt        tc  1   cow         tc  5   chickens         tc  1   airplane

User · Answer

C  6 adds a new feature just for this  extension Add methods   This has always been possible for VB net but is now available in C    Now you don t have to add Add   methods to your classes directly  you can implement them as extension methods   When extending any enumerable type with an Add   method  you ll be able to use it in collection initializer expressions   So you don t have to derive from lists explicitly anymore  as mentioned in another answer   you can simply extend it   public static class TupleListExtensions       public static void Add lt T1  T2 gt  this IList lt Tuple lt T1  T2 gt  gt  list              T1 item1  T2 item2                list Add Tuple Create item1  item2               public static void Add lt T1  T2  T3 gt  this IList lt Tuple lt T1  T2  T3 gt  gt  list              T1 item1  T2 item2  T3 item3                list Add Tuple Create item1  item2  item3                  and so on        This will allow you to do this on any class that implements IList lt  gt    var numbers   new List lt Tuple lt int  string gt  gt          1   one           2   two           3   three           4   four           5   five        var points   new ObservableCollection lt Tuple lt double  double  double gt  gt          0  0  0          1  2  3          -4  -2  42         Of course you re not restricted to extending collections of tuples  it can be for collections of any specific type you want the special syntax for   public static class BigIntegerListExtensions       public static void Add this IList lt BigInteger gt  list          params byte   value                list Add new BigInteger value               public static void Add this IList lt BigInteger gt  list          string value                list Add BigInteger Parse value             var bigNumbers   new List lt BigInteger gt        new BigInteger 1      constructor BigInteger int      2222222222L           implicit operator BigInteger long      3333333333UL          implicit operator BigInteger ulong        4  4  4  4  4  4  4  4                     extension Add byte         55555555555555555555555555555555555555      extension Add string         C  7 will be adding in support for tuples built into the language  though they will be of a different type  System ValueTuple instead    So to it would be good to add overloads for value tuples so you have the option to use them as well   Unfortunately  there are no implicit conversions defined between the two   public static class ValueTupleListExtensions       public static void Add lt T1  T2 gt  this IList lt Tuple lt T1  T2 gt  gt  list          ValueTuple lt T1  T2 gt  item    gt  list Add item ToTuple         This way the list initialization will look even nicer   var points   new List lt Tuple lt int  int  int gt  gt         0  0  0        1  2  3        -1  12  -73        But instead of going through all this trouble  it might just be better to switch to using ValueTuple exclusively   var points   new List lt  int  int  int  gt         0  0  0        1  2  3        -1  12  -73

User · Answer

Why do like tuples  It s like anonymous types  no names  Can not understand structure of data   I like classic classes  class FoodItem        public int Position   get  set         public string Name   get  set       List lt FoodItem gt  list   new List lt FoodItem gt         new FoodItem   Position   1  Name    apple          new FoodItem   Position   2  Name    kiwi

User · Answer

Yes  This is possible      The     syntax of the collection initializer works on any IEnumerable   type which has an Add method with the correct amount of arguments    Without bothering how that works under the covers  that means you can   simply extend from List lt T gt   add a custom Add method to initialize your   T  and you are done    public class TupleList lt T1  T2 gt    List lt Tuple lt T1  T2 gt  gt        public void Add  T1 item  T2 item2                 Add  new Tuple lt T1  T2 gt   item  item2                This allows you to do the following   var groceryList   new TupleList lt int  string gt          1   kiwi           5   apples           3   potatoes           1   tomato

User · Answer

You can do this by calling the constructor each time with is slightly better  var tupleList   new List lt Tuple lt int  string gt  gt        new Tuple lt int  string gt  1   cow         new Tuple lt int  string gt   5   chickens         new Tuple lt int  string gt   1   airplane

[c#] How to easily initialize a list of Tuples?

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