Linq's Aggregate Function, How to make a CSV String

Question

I'd like to make a comma seperated value string with Linq's Aggregate function. Anyone know how to do this?

Given an array of strings like this:

var authors = new string[] {"author 1", "author 2", "author 3"};

How do I get a single string like this author 1, author 2, author 3? I'm thinking something like authors.Aggregate(author => author + ",") might be able to do this but not sure.

Ideas?

Possible duplicate of [LINQ Aggregate algorithm explained](http://stackoverflow.com/questions/7105505/linq-aggregate-algorithm-explained) — Jamiec, Oct 05 '15 at 14:49

score 12 · Accepted Answer · answered Sep 12 '10 at 22:28

12

If you're only looking to comma-separate them, just use string.Join:

string.Join(", ", authors);

This will work with any IEnumerable<string> (at least in .NET 4.0), but has worked with arrays of strings since 1.0.

answered Sep 12 '10 at 22:28

Bennor McCarthy

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O Cool, I guess Aggregate is not really what I need. Looks like Join is the right thing. I'll give try this... thanks. – Paul Fryer Sep 12 '10 at 22:37
Good call - I forgot about that method! – ColinE Jul 05 '11 at 08:15

Ani · Answer 2 · 2010-09-13T14:06:47.867

7

As Bennor McCarthy says, you'd be much better off using string.Join for this purpose. If you really do want to use Enumerable.Aggregate though, this should do:

string csvString = authors.Aggregate((csvSoFar, author) => csvSoFar + ", " + author);

This is roughly equivalent to:

string csvString = authors.First();

foreach (string author in authors.Skip(1))
{
    csvString += ", " + author;
}

edited Sep 13 '10 at 14:06

answered Sep 12 '10 at 22:29

Ani

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Thanks, Ya looks like Join is much is a much simpler approach for this task. – Paul Fryer Sep 12 '10 at 22:38

Linq's Aggregate Function, How to make a CSV String

2 Answers2