Best way to convert IEnumerable to string?

Question

Why isn\'t it possible to use fluent language on string?

For example:

var x = \"asdf1234\";
var y = new string(x.TakeWhile(char.IsLetter         


        

Answer 1

Assuming that you're looking predominantly for performance, then something like this should be substantially faster than any of your examples:

string x = "asdf1234";
string y = x.LeadingLettersOnly();

// ...

public static class StringExtensions
{
    public static string LeadingLettersOnly(this string source)
    {
        if (source == null)
            throw new ArgumentNullException("source");

        if (source.Length == 0)
            return source;

        char[] buffer = new char[source.Length];
        int bufferIndex = 0;

        for (int sourceIndex = 0; sourceIndex < source.Length; sourceIndex++)
        {
            char c = source[sourceIndex];

            if (!char.IsLetter(c))
                break;

            buffer[bufferIndex++] = c;
        }
        return new string(buffer, 0, bufferIndex);
    }
}