Concat todas las cadenas dentro de una Lista usando LINQ

Question

Concat todas las cadenas dentro de una Lista usando LINQ

¿Hay alguna expresión LINQ fácil para concatenar todos mis elementos de colección List<string> en un único string con un carácter delimitador?

¿Qué pasa si la colección es de objetos personalizados en lugar de string? Imagine que necesito concatenar en object.Name.

443

c#.net-3.5 linq

Author: shA.t, 2009-02-18

Source

9 answers

En. NET 4.0 y versiones posteriores:

String.Join(delimiter, list);

Es suficiente.

767

Author: Sedat Kapanoglu,
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2018-09-04 23:01:01

Esto es para una matriz de cadenas:

string.Join(delimiter, array);

Esto es para una lista:

string.Join(delimiter, list.ToArray());

Y esto es para una lista de objetos personalizados:

string.Join(delimiter, list.Select(i => i.Boo).ToArray());

104

Author: Alexander Prokofyev,
Warning: date(): Invalid date.timezone value 'Europe/Kyiv', we selected the timezone 'UTC' for now. in /var/www/agent_stack/data/www/ajaxhispano.com/template/agent.layouts/content.php on line 61
2009-02-18 05:53:24

using System.Linq;

public class Person
{
  string FirstName { get; set; }
  string LastName { get; set; }
}

List<Person> persons = new List<Person>();

string listOfPersons = string.Join(",", persons.Select(p => p.FirstName));

50

Author: dev.bv,
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2015-03-05 14:40:11

Buena pregunta. He estado usando

List<string> myStrings = new List<string>{ "ours", "mine", "yours"};
string joinedString = string.Join(", ", myStrings.ToArray());

No es LINQ, pero funciona.

22

Author: Jacob Proffitt,
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2009-02-18 01:00:57

List<string> strings = new List<string>() { "ABC", "DEF", "GHI" };
string s = strings.Aggregate((a, b) => a + ',' + b);

6

Author: Peter McG,
Warning: date(): Invalid date.timezone value 'Europe/Kyiv', we selected the timezone 'UTC' for now. in /var/www/agent_stack/data/www/ajaxhispano.com/template/agent.layouts/content.php on line 61
2009-02-18 04:36:40

Creo que si defines la lógica en un método de extensión el código será mucho más legible:

public static class EnumerableExtensions { 
  public static string Join<T>(this IEnumerable<T> self, string separator) {  
    return String.Join(separator, self.Select(e => e.ToString()).ToArray()); 
  } 
} 

public class Person {  
  public string FirstName { get; set; }  
  public string LastName { get; set; }  
  public override string ToString() {
    return string.Format("{0} {1}", FirstName, LastName);
  }
}  

// ...

List<Person> people = new List<Person>();
// ...
string fullNames = people.Join(", ");
string lastNames = people.Select(p => p.LastName).Join(", ");

5

Author: Jordão,
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2010-10-19 17:37:59

He hecho esto usando linq:

var oCSP = (from P in db.Products select new { P.ProductName });

string joinedString = string.Join(",", oCSP.Select(p => p.ProductName));

1

Author: Biddut,
Warning: date(): Invalid date.timezone value 'Europe/Kyiv', we selected the timezone 'UTC' for now. in /var/www/agent_stack/data/www/ajaxhispano.com/template/agent.layouts/content.php on line 61
2018-08-13 09:12:55

Puedes usar simplemente:

List<string> items = new List<string>() { "foo", "boo", "john", "doe" };

Console.WriteLine(string.Join(",", items));

Feliz codificación!

1

Author: Nishanth Shaan,
Warning: date(): Invalid date.timezone value 'Europe/Kyiv', we selected the timezone 'UTC' for now. in /var/www/agent_stack/data/www/ajaxhispano.com/template/agent.layouts/content.php on line 61
2018-09-13 12:44:55

score 432 · Accepted Answer

Usando LINQ, esto debería funcionar;

string delimiter = ",";
List<string> items = new List<string>() { "foo", "boo", "john", "doe" };
Console.WriteLine(items.Aggregate((i, j) => i + delimiter + j));

Descripción de la clase:

public class Foo
{
    public string Boo { get; set; }
}

Uso:

class Program
{
    static void Main(string[] args)
    {
        string delimiter = ",";
        List<Foo> items = new List<Foo>() { new Foo { Boo = "ABC" }, new Foo { Boo = "DEF" },
            new Foo { Boo = "GHI" }, new Foo { Boo = "JKL" } };

        Console.WriteLine(items.Aggregate((i, j) => new Foo{Boo = (i.Boo + delimiter + j.Boo)}).Boo);
        Console.ReadKey();

    }
}

Y aquí está mi mejor:)

items.Select(i => i.Boo).Aggregate((i, j) => i + delimiter + j)