Aggregate a List<int> to a string using (i, j) => i + "delimiter" + j

Question

I'm triyng to do a quick Haskell-like aggregation in Linq (C#), to turn a List into a string in the format "i^j^k..." etc.

is this possible in one query, or should I just do it the old-fasioned

foreach (int i in list)
{
     string+= i + "^"
}

(p.s. yes, that's pseudocode and wouldn't compile.)

Answer 1

Use string.Join:

string.Join("^", list.Select(x => x.ToString()).ToArray())

In this particular case it may be more efficient to use StringBuilder directly as Append(int) may avoid creating the temporary strings. Unless this turns out to be a bottleneck, however, I'd stick to this simple single expression.

Answer 2

It's much more efficient to use a StringBuilder instance here.

Answer 3

It's definitely possible in LINQ (see other answer for syntax).

However, you might consider using a StringBuilder instead.

StringBuilder sb = new StringBuilder();
foreach (int i in list) sb.Append(i.ToString());

In you case, better is:

String.Join("^", list.ToArray());

that uses StringBuilder to accomplish the same work.

Answer 4

You can use the Aggregate extension:

string s = list.Aggregate<int, string>(String.Empty, (x, y) => (x.Length > 0 ? x + "^" : x) + y.ToString());