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

RegexOptions options = RegexOptions.None;
Regex regex = new Regex(@"[ ]{2,}", options);     
tempo = regex.Replace(tempo, @" ");

Answer 2

string xyz = "1   2   3   4   5";
xyz = string.Join( " ", xyz.Split( new char[] { ' ' }, StringSplitOptions.RemoveEmptyEntries ));

Answer 3

while (str.IndexOf("  ") != -1)
  str = str.Replace("  ", " ");

Non regex way.

Answer 4

Consolodating other answers, per Joel, and hopefully improving slightly as I go:

You can do this with Regex.Replace():

string s = Regex.Replace (
    "   1  2    4 5", 
    @"[ ]{2,}", 
    " "
    );

Or with String.Split():

static class StringExtensions
{
    public static string Join(this IList<string> value, string separator)
    {
        return string.Join(separator, value.ToArray());
    }
}

//...

string s = "     1  2    4 5".Split (
    " ".ToCharArray(), 
    StringSplitOptions.RemoveEmptyEntries
    ).Join (" ");

Answer 5

It's much simpler than all that:

while(str.Contains("  ")) str = str.Replace("  ", " ");

Answer 6

I like to use:

myString = Regex.Replace(myString, @"\s+", " ");

Since it will catch runs of any kind of whitespace (e.g. tabs, newlines, etc.) and replace them with a single space.

Answer 7

If this is in a lengthy loop with optimization concerns, I would suggest doing a timing comparison of the given solutions with a simple char array copy that skips the extra spaces.

Answer 8

I just wrote a new Join that I like, so I thought I'd re-answer, with it:

public static string Join<T>(this IEnumerable<T> source, string separator)
{
    return string.Join(separator, source.Select(e => e.ToString()).ToArray());
}

One of the cool things about this is that it work with collections that aren't strings, by calling ToString() on the elements. Usage is still the same:

//...

string s = "     1  2    4 5".Split (
    " ".ToCharArray(), 
    StringSplitOptions.RemoveEmptyEntries
    ).Join (" ");

Answer 9

myString = Regex.Replace(myString, " {2,}", " ");

Answer 10

thanks.. this thread helped me a lot

Answer 11

I think Matt's answer is the best, but I don't believe it's quite right. If you want to replace newlines, you must use:

myString = Regex.Replace(myString, @"\s+", " ", RegexOptions.Multiline);