Join a string[] Without Using string.Join

Question

This question is for academic purposes only.

Let's assume I have the following code ...

var split = line.Split(new[] { ',' }, System.StringSplitOptions.RemoveEmptyEntries);
var elem = new XElement("shop");
elem.SetAttributeValue("name", split.Take(split.Length - 1));  <=====
elem.SetAttributeValue("tin", split.Last());

And I would like the line with the arrow to produce the same result as this ...

string.Join(string.Empty, split.Take(split.Length - 1));

... without using string.Join.

Is that possible? I can't seem to find a LINQ statement to do it ... hopefully y'all already know!

Answer 1

Using a StringBuilder for O(n) performance:

split
    .Take(split.Length - 1)
    .Aggregate(new StringBuilder(), (sb, s) => sb.Append(s)).ToString();

If the object is to avoid the awkwardness of a tree of combined LINQ calls and static methods, then a straightforward solution is an extension method:

public static string Join(this IEnumerable<string> self, string separator = "")
{
    return string.Join(separator, self);
}

And then:

split.Take(split.Length - 1).Join();

I find this to read much better than using string.Join in complicated expressions.