How do I replace multiple spaces with a single space in C#?

Question

How can I replace multiple spaces in a string with only one space in C#?

Example:

1 2 3  4    5

would be:

1 2 3 4 5         


        

Answer 1

Regex can be rather slow even with simple tasks. This creates an extension method that can be used off of any string.

    public static class StringExtension
    {
        public static String ReduceWhitespace(this String value)
        {
            var newString = new StringBuilder();
            bool previousIsWhitespace = false;
            for (int i = 0; i < value.Length; i++)
            {
                if (Char.IsWhiteSpace(value[i]))
                {
                    if (previousIsWhitespace)
                    {
                        continue;
                    }

                    previousIsWhitespace = true;
                }
                else
                {
                    previousIsWhitespace = false;
                }

                newString.Append(value[i]);
            }

            return newString.ToString();
        }
    }

It would be used as such:

string testValue = "This contains     too          much  whitespace."
testValue = testValue.ReduceWhitespace();
// testValue = "This contains too much whitespace."