CODEWITHSUNDEEP
c#stringlistalphabetical
Chaddeus
Chaddeus

Reputation: 13356

Break out an alphabetized list by starting letter [C#]

I have a list, it's already sorted in alphabetical order. I'd like to break it into sections corresponding with the letter is starts with, like so:

A

B

C

...

I could do something like:

foreach item in list if item startsWith A ... do something if item startsWith B ... do something if item startsWith C ... do something

etc...

but is there a more concise way to do this?

Upvotes: 0

Views: 395

Answers (3)

jasonp
jasonp

Reputation: 410

var list = new List<string>() {"a1", "a2", "b1", "b2"};
var grouped = from item in list
              group item by item.First() into g
              select new {StartsWith = g.Key, Items = g};

Upvotes: 1

Kevin Gosse
Kevin Gosse

Reputation: 39007

You can use the Linq GroupBy method to create your sections:

foreach (var group in list.GroupBy(i => i[0]))
{
   Console.WriteLine("Section: " + group.Key);

   foreach (var elt in group)
   {
      Console.WriteLine(elt);
   }
}

Upvotes: 3

Petar Ivanov
Petar Ivanov

Reputation: 93030

Just keep track of the current first letter as you go:

char first = '\0';
foreach(string item in list){
     if(item[0] != first){
         first = item[0];
         Console.WriteLine(first);
     }

     Console.WriteLine("  *  " + item);
}

Upvotes: 2

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