C# object[] to delimited string

Question

This rather inelegant method takes an input array of objects and outputs a string result, which is the result of ToString() for each element, space separated.

string Format(object[] args)
{
   var res = string.Empty;
   foreach (var o in args)
   {
      res += o.ToString();
      if (o != args.Last())
         res += " ";
   }
}

Surely there is a C# method hidden somewhere to do this type of operation, or if not, a more elegant way to write it using Linq? Another concern with how I have written this method is the garbage generation by building the string incrementally.

What @McGarnagle said, plus it's going to fall over if `o` is null. — Moo-Juice, Jul 25 '13 at 20:42
What @Moo-Juice said, plus if you pass in value types they all get boxed & if there are a lot of objects you'd be better of using a `StringBuilder`. Plus Format is a bad name as you're not actually doing any formatting... — Trevor Pilley, Jul 25 '13 at 20:43
Remember it a object so I think o[0].ToString() would give you the string object. — Bit, Jul 25 '13 at 20:45
Looking at the implementation of String.Join, it meets all the requirements: uses stringbuilder to avoid garbage, calls ToString on each element for me, and is more elegant than even linq since it is a single static method call. This is a different accepted answer than the proposed duplicate question. — James, Jul 25 '13 at 21:07
@James `String.Join` is the highest up voted answer on that possible dupe. — Steven Jeuris, Jul 25 '13 at 22:28
Edited my question so that it is not specifically about "how to do this with Linq" but how to do this operation more 'elegantly'. Since string.Join is definitely more elegent and deals with the garbage generation issue, I would hope that future people see this question and its accepted answer rather than the other proposed duplicate. — James, Jul 26 '13 at 22:03

score 12 · Accepted Answer · answered Jul 25 '13 at 20:44

12

var res = String.Join(" ", args);

answered Jul 25 '13 at 20:44

I4V

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score 3 · Answer 2 · answered Jul 25 '13 at 20:46

3

var res = String.Join(" ", args.Select(x=> x != null ? x.ToString() : ""));

Will join together a string representation of each item.

answered Jul 25 '13 at 20:46

3

No need for this extra null check, String.Join already handles it. – I4V Jul 25 '13 at 20:51
I'm calling `ToString()`. A null value will cause a `NullReferenceException` – Jul 25 '13 at 20:51
But String.Join already uses `.ToString()` – I4V Jul 25 '13 at 20:52
String.Join does .ToString() and the null test for you. – James Jul 25 '13 at 21:10
Ah, didn't know about that overload of String.Join. – Jul 25 '13 at 21:39

evanmcdonnal · Answer 3 · 2013-07-25T21:07:56.893

1

You can use the aggregate method which I tend to prefer.

args.Where(x => x != null).Aggregate((c, n) => c.ToString() + " " + n.ToString());

edited Jul 25 '13 at 21:07

answered Jul 25 '13 at 20:48

evanmcdonnal

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@I4V well obv you get a null reference exception on index 2. `args.Where(x => x != null).Aggregate( ... )` easily solves that problem though. – evanmcdonnal Jul 25 '13 at 21:07

C# object[] to delimited string

3 Answers3