Reputation: 190679

Building a string from List<string> in C#

The List<string> has ("ABC","","DEF","","XYZ"), how can I get the string "ABC::DEF::XYZ" out of the List in C#?

ADDED

List<string> strings = new List<string> {"ABC","","DEF","","XYZ"};
string joined = string.Join("::", strings.ToArray());
Console.WriteLine(joined);

gives ABC::::DEF::::XYZ, not ABC::DEF::XYZ, how can one skip the empty strings ("") in a list?

Upvotes: 2

Answers (7)

Ani

Reputation: 113402

You can do:

List<string> strings = ...
string joined = string.Join(":", strings.ToArray());

In .NET 4.0, you can leave out the ToArray() call.

EDIT: Based on your update that indicates that you want to skip empty strings and use two colons as the delimiter, you can do:

// Use !string.IsNullOrEmpty or !string.IsNullOrWhiteSpace if more appropriate.   
string[] filtered = list.Where(s => s != string.Empty) 
                        .ToArray();

string joined = string.Join("::", filtered);

Upvotes: 7

V4Vendetta

Reputation: 38200

I think you can have a look at The suggested method

post this you can simply do string.Join(",", strings.ToArray())

(replace the empty strings with ::)

Upvotes: 0

Justin Morgan

Reputation: 30705

string result = string.Join("::", list.Where(s => !string.IsNullOrEmpty(s)).ToArray());

Upvotes: 2

Manish Basantani

Reputation: 17499

string.Join("::", strings.Where(item=>!string.IsNullOrEmpty(item)).ToArray());

Upvotes: 1

Dan Tao

Reputation: 128317

Using string.Join with ToArray would work.

As Ani said, if you're on .NET 4.0, you could leave out the ToArray.

If you're not on .NET 4.0 but you don't want the overhead of the ToArray call, you could write a method to create a StringBuilder, append every item in the List<string> plus your delimiter (skipping the delimiter after the last item), and return the result of ToString at the end.

Upvotes: 0