C# String.Split : Best way to specify whitespace AND additional separator characters?

Question

With any of the following variants all white-space characters are defined as splitting character :

string[] words = phrase.Split(null); 
string[] words = phrase.Split(new char[0]); 
string[] words = phrase.Split((char[])null); 
string[] words = phrase.Split(default(Char[])); 
string[] words = phrase.Split(null as char[]);

But is there also a way to define whitespace AND additional separator characters like comma ( , ) or hyphen (-) without nested calls of String.Split and without explicitly defining each of the white space characters ?

The goal is high performance, rather than concise code

Answer 1

You could use Regex.Split instead, which allows you to split on a Regex pattern:

string[] words = Regex.Split(phrase, "[\s,-]");

The pattern [\\s,-] will split on any whitespace ( \\s ), or a comma or hyphen literal ( , , - )

Be sure to add a reference to System.Text.RegularExpressions

using System.Text.RegularExpressions;

Answer 2

As the official documentation says:

Performance Considerations

The Split methods allocate memory for the returned array object and a String object for each array element. If your application requires optimal performance or if managing memory allocation is critical in your application, consider using the IndexOf or IndexOfAny method, and optionally the Compare method, to locate a substring within a string.

If you need high performance you should use Span<string> and the methods IndexOf and Slice .