Concat all strings inside a List using LINQ


Question

Is there any easy LINQ expression to concatenate my entire List<string> collection items to a single string with a delimiter character?

What if the collection is of custom objects instead of string? Imagine I need to concatenate on object.Name.

1
497
9/2/2017 8:41:18 AM

Accepted Answer

By using LINQ, this should work;

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

class description:

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

Usage:

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();

    }
}

And here is my best :)

items.Select(i => i.Boo).Aggregate((i, j) => i + delimiter + j)
485
4/22/2016 11:46:43 AM

In .NET 4.0 or later versions:

String.Join(delimiter, list);

is sufficient.


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