Shortcut for creating single item list in C

Question

In C   is there an inline shortcut to instantiate a List lt T gt  with only one item   I m currently doing   new List lt string gt   new string      title         Having this code everywhere reduces readability   I ve thought of using a utility method like this   public static List lt T gt  SingleItemList lt T gt   T value         return  new List lt T gt   new T     value           So I could do   SingleItemList  title      Is there a shorter   cleaner way   Thanks

User · Answer

new      item    ToList      It s shorter than  new List lt string gt     item       and you don t have to specify the type

User · Answer

Michael s idea of using extension methods leads to something even simpler   public static List lt T gt  InList lt T gt  this T item        return new List lt T gt    item        So you could do this   List lt string gt  foo    Hello  InList      I m not sure whether I like it or not  mind you

User · Answer

Inspired by the other answers  and so I can pick it up whenever I need it    but with naming style aligned with F   which has a standard singleton function per data structure     namespace System Collections Generic       public static class List               public static List lt T gt  Singleton lt T gt  T value    gt  new List lt T gt  1    value                except for ResizeArray itself of course  hence this question       In practice I actually name it Create to align with other helpers I define such as Tuple Create  Lazy Create 2   LazyTask Create etc   namespace System Collections Generic       public static class List               public static List lt T gt  Create lt T gt  T value    gt  new List lt T gt  1    value               2    namespace System       public static class Lazy               public static Lazy lt T gt  Create lt T gt  Func lt T gt  factory    gt  new Lazy lt T gt  factory

User · Answer

Use an extension method with method chaining   public static List lt T gt  WithItems this List lt T gt  list  params T   items        list AddRange items       return list      This would let you do this   List lt string gt  strings   new List lt string gt    WithItems  Yes      or  List lt string gt  strings   new List lt string gt    WithItems  Yes    No    Maybe So      Update  You can now use list initializers   var strings   new List lt string gt     This    That    The Other       See http   msdn microsoft com en-us library bb384062 v vs 90  aspx

User · Answer

I ve got this little function   public static class CoreUtil           public static IEnumerable lt T gt  ToEnumerable lt T gt  params T   items                return items            Since it doesn t prescribe a concrete return type this is so generic that I use it all over the place  Your code would look like  CoreUtil ToEnumerable  title   ToList      But of course it also allows  CoreUtil ToEnumerable  title1    title2    title3   ToArray      I often use it in when I have to append prepend one item to the output of a LINQ statement  For instance to add a blank item to a selection list   CoreUtil ToEnumerable     Concat context TrialTypes Select t   gt  t Name     Saves a few ToList   and Add statements    Late answer  but I stumbled upon this oldie and thought this could be helpful

User · Answer

Yet another way  found on  C   Net Little wonders   unfortunately  the site doesn t exist anymore    Enumerable Repeat  value  1  ToList

User · Answer

For a single item enumerable in java it would be Collections singleton  string     In c  this is going to be more efficient than a new List   public class SingleEnumerator lt T gt    IEnumerable lt T gt        private readonly T m Value       public SingleEnumerator T value                m Value   value             public IEnumerator lt T gt  GetEnumerator                 yield return m Value             IEnumerator IEnumerable GetEnumerator                 yield return m Value            but is there a simpler way using the framework

User · Answer

For a single item enumerable in java it would be Collections singleton  string     In c  this is going to be more efficient than a new List   public class SingleEnumerator lt T gt    IEnumerable lt T gt        private readonly T m Value       public SingleEnumerator T value                m Value   value             public IEnumerator lt T gt  GetEnumerator                 yield return m Value             IEnumerator IEnumerable GetEnumerator                 yield return m Value            but is there a simpler way using the framework

User · Answer

Yet another way  found on  C   Net Little wonders   unfortunately  the site doesn t exist anymore    Enumerable Repeat  value  1  ToList

User · Answer

Michael s idea of using extension methods leads to something even simpler   public static List lt T gt  InList lt T gt  this T item        return new List lt T gt    item        So you could do this   List lt string gt  foo    Hello  InList      I m not sure whether I like it or not  mind you

User · Answer

You can also do  new List lt string gt       string here

User · Answer

I would just do   var list   new List lt string gt     hello

User · Answer

Use an extension method with method chaining   public static List lt T gt  WithItems this List lt T gt  list  params T   items        list AddRange items       return list      This would let you do this   List lt string gt  strings   new List lt string gt    WithItems  Yes      or  List lt string gt  strings   new List lt string gt    WithItems  Yes    No    Maybe So      Update  You can now use list initializers   var strings   new List lt string gt     This    That    The Other       See http   msdn microsoft com en-us library bb384062 v vs 90  aspx

User · Answer

Try var  var s   new List lt string gt     a    bk    ca    d

User · Answer

Simply use this   List lt string gt  list   new List lt string gt       single value       You can even omit the    braces   List lt string gt  list   new List lt string gt     single value       Update  of course this also works for more than one entry   List lt string gt  list   new List lt string gt     value1    value2

User · Answer

A different answer to my earlier one  based on exposure to the Google Java Collections   public static class Lists       public static List lt T gt  Of lt T gt  T item                return new List lt T gt    item              Then   List lt string gt  x   Lists Of  Hello      I advise checking out the GJC - it s got lots of interesting stuff in   Personally I d ignore the  alpha  tag - it s only the open source version which is  alpha  and it s based on a very stable and heavily used internal API

User · Answer

A different answer to my earlier one  based on exposure to the Google Java Collections   public static class Lists       public static List lt T gt  Of lt T gt  T item                return new List lt T gt    item              Then   List lt string gt  x   Lists Of  Hello      I advise checking out the GJC - it s got lots of interesting stuff in   Personally I d ignore the  alpha  tag - it s only the open source version which is  alpha  and it s based on a very stable and heavily used internal API

User · Answer

Use an extension method with method chaining   public static List lt T gt  WithItems this List lt T gt  list  params T   items        list AddRange items       return list      This would let you do this   List lt string gt  strings   new List lt string gt    WithItems  Yes      or  List lt string gt  strings   new List lt string gt    WithItems  Yes    No    Maybe So      Update  You can now use list initializers   var strings   new List lt string gt     This    That    The Other       See http   msdn microsoft com en-us library bb384062 v vs 90  aspx

User · Answer

Use an extension method with method chaining   public static List lt T gt  WithItems this List lt T gt  list  params T   items        list AddRange items       return list      This would let you do this   List lt string gt  strings   new List lt string gt    WithItems  Yes      or  List lt string gt  strings   new List lt string gt    WithItems  Yes    No    Maybe So      Update  You can now use list initializers   var strings   new List lt string gt     This    That    The Other       See http   msdn microsoft com en-us library bb384062 v vs 90  aspx

User · Answer

I would just do   var list   new List lt string gt     hello

User · Answer

A different answer to my earlier one  based on exposure to the Google Java Collections   public static class Lists       public static List lt T gt  Of lt T gt  T item                return new List lt T gt    item              Then   List lt string gt  x   Lists Of  Hello      I advise checking out the GJC - it s got lots of interesting stuff in   Personally I d ignore the  alpha  tag - it s only the open source version which is  alpha  and it s based on a very stable and heavily used internal API

User · Answer

new      item    ToList      It s shorter than  new List lt string gt     item       and you don t have to specify the type

User · Answer

Simply use this   List lt string gt  list   new List lt string gt       single value       You can even omit the    braces   List lt string gt  list   new List lt string gt     single value       Update  of course this also works for more than one entry   List lt string gt  list   new List lt string gt     value1    value2

User · Answer

Michael s idea of using extension methods leads to something even simpler   public static List lt T gt  InList lt T gt  this T item        return new List lt T gt    item        So you could do this   List lt string gt  foo    Hello  InList      I m not sure whether I like it or not  mind you

User · Answer

Simply use this   List lt string gt  list   new List lt string gt       single value       You can even omit the    braces   List lt string gt  list   new List lt string gt     single value       Update  of course this also works for more than one entry   List lt string gt  list   new List lt string gt     value1    value2

User · Answer

Try var  var s   new List lt string gt     a    bk    ca    d

User · Answer

var list   new List lt string gt  1     hello       Very similar to what others have posted  except that it makes sure to only allocate space for the single item initially   Of course  if you know you ll be adding a bunch of stuff later it may not be a good idea  but still worth mentioning once

User · Answer

var list   new List lt string gt  1     hello       Very similar to what others have posted  except that it makes sure to only allocate space for the single item initially   Of course  if you know you ll be adding a bunch of stuff later it may not be a good idea  but still worth mentioning once

User · Answer

var list   new List lt string gt  1     hello       Very similar to what others have posted  except that it makes sure to only allocate space for the single item initially   Of course  if you know you ll be adding a bunch of stuff later it may not be a good idea  but still worth mentioning once

User · Answer

You can also do  new List lt string gt       string here

User · Answer

Simply use this   List lt string gt  list   new List lt string gt       single value       You can even omit the    braces   List lt string gt  list   new List lt string gt     single value       Update  of course this also works for more than one entry   List lt string gt  list   new List lt string gt     value1    value2

User · Answer

I would just do   var list   new List lt string gt     hello

User · Answer

Inspired by the other answers  and so I can pick it up whenever I need it    but with naming style aligned with F   which has a standard singleton function per data structure     namespace System Collections Generic       public static class List               public static List lt T gt  Singleton lt T gt  T value    gt  new List lt T gt  1    value                except for ResizeArray itself of course  hence this question       In practice I actually name it Create to align with other helpers I define such as Tuple Create  Lazy Create 2   LazyTask Create etc   namespace System Collections Generic       public static class List               public static List lt T gt  Create lt T gt  T value    gt  new List lt T gt  1    value               2    namespace System       public static class Lazy               public static Lazy lt T gt  Create lt T gt  Func lt T gt  factory    gt  new Lazy lt T gt  factory

User · Answer

Michael s idea of using extension methods leads to something even simpler   public static List lt T gt  InList lt T gt  this T item        return new List lt T gt    item        So you could do this   List lt string gt  foo    Hello  InList      I m not sure whether I like it or not  mind you

User · Answer

You can also do  new List lt string gt       string here

User · Answer

A different answer to my earlier one  based on exposure to the Google Java Collections   public static class Lists       public static List lt T gt  Of lt T gt  T item                return new List lt T gt    item              Then   List lt string gt  x   Lists Of  Hello      I advise checking out the GJC - it s got lots of interesting stuff in   Personally I d ignore the  alpha  tag - it s only the open source version which is  alpha  and it s based on a very stable and heavily used internal API

User · Answer

You can also do  new List lt string gt       string here

User · Answer

I would just do   var list   new List lt string gt     hello

User · Answer

var list   new List lt string gt  1     hello       Very similar to what others have posted  except that it makes sure to only allocate space for the single item initially   Of course  if you know you ll be adding a bunch of stuff later it may not be a good idea  but still worth mentioning once

User · Answer

I ve got this little function   public static class CoreUtil           public static IEnumerable lt T gt  ToEnumerable lt T gt  params T   items                return items            Since it doesn t prescribe a concrete return type this is so generic that I use it all over the place  Your code would look like  CoreUtil ToEnumerable  title   ToList      But of course it also allows  CoreUtil ToEnumerable  title1    title2    title3   ToArray      I often use it in when I have to append prepend one item to the output of a LINQ statement  For instance to add a blank item to a selection list   CoreUtil ToEnumerable     Concat context TrialTypes Select t   gt  t Name     Saves a few ToList   and Add statements    Late answer  but I stumbled upon this oldie and thought this could be helpful

[c#] Shortcut for creating single item list in C#

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