Regex String.split(/\s*/) gives different results in JavaScript and C#

February 19, 2022

I have a Regex in JS which does not produce same results in C#:

//javascript
var password = "pass";
var arrPws = password.split(/\s*/);

gives me a String[] result like the following

But when I try to reproduce it in C# I get a slightly different output:

//c#
using System.Text.RegularExpressions;

var password = "pass";
var arrPwd = Regex.Split(password,@"\s*");

the C# code adds an extra "" in the beginning and end like following
How do I eliminate the extra "" in C#?

>Solution :

For a quick fix to the .NET code, you may split on (?<=.)\s*(?=.):

using System.Text.RegularExpressions;

var password = "pass";
var arrPwd = Regex.Split(password,@"(?<=.)\s*(?=.)");
foreach(var item in arrPwd)
{
    Console.WriteLine(item.ToString());
}

This prints:

p
a
s
s

The issue you are seeing has to do with the behavior of \s*. On .NET’s regex engine, \s* matches the zero width markers at the very start and end of the input, but not in JavaScript’s engine.

If you just want an array of all characters in the string, use string#ToCharArray().