Using String.Join for multiple items in a List

Question

I have an entity like this:

public class Task
{
    public string TaskID { get; set; }
    public string Description { get; set; }
    public string IsComplete { get; set; }
}

I have a collection of Tasks like:

List<Task> tasks = new List<Task>();
tasks.Add(new Task() { TaskID = "1", Description = "A", IsComplete = "Yes" });
tasks.Add(new Task() { TaskID = "2", Description = "B", IsComplete = "No" });

I am trying to get the following delimited string from this collection:

1#Yes,2#No

I've managed to get as far as:

string delimitedString = String.Join(",", tasks.ToList().Select(l => l.TaskID));

...How do I further select and separate additional fields?

Yuval Itzchakov · Accepted Answer · 2015-09-02 12:28:45Z

12

Like this:

string delimitedString = 
           string.Join(",", tasks.Select(
                                  l => string.Format("{0}#{1}", l.TaskID, l.IsComplete)));

If you're using C#-6:

string delimitedString = 
            string.Join(",", tasks.Select(
                                   l => $"{l.TaskID}#{l.IsComplete}"));

edited Sep 2, 2015 at 12:28

answered Sep 2, 2015 at 12:25

Yuval Itzchakov

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1 Comment

notAnonymousAnymore Over a year ago

Thanks, works great. You left out a closing bracket btw

Community · Accepted Answer · 2017-05-23 12:06:14Z

5

You could do it the way Yuval Itzchakov proposed, but I'd rather implement a new method in Task that you can call - just to keep it easier to read.

public class Task
{
    ...
    public String ToDelimitedString()
    {
        return String.Format("{0}#{1}", TaskId, IsComplete);
    }
}

And then call it like this:

var delimString = String.Join(",", tasks.Select(t => t.ToDelimitedString()));

This way you have your format in one place and can call it from anywhere without inconsistencies.

By the way: I'd also try to find a different name for the class to avoid any possible confusion with System.Threading.Tasks.Task.

edited May 23, 2017 at 12:06

CommunityBot

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answered Sep 2, 2015 at 12:29

germi

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Comments

Gilthans · Accepted Answer · 2015-09-02 12:29:45Z

2

I think what you need is to implement a ToString for the Task, so it displays what you want.

If you can't (it isnt your code), implement a separate function:

private string StringifyTask(Task task)
{
    return string.Format("{0}#{1}", task.TaskId, task.IsComplete);
}

And then use StringifyTask as the argument of Select. Also - note you don't actually need the ToList before the Linq statement.

answered Sep 2, 2015 at 12:29

Gilthans

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