How do I replace multiple spaces with a single spa

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

try this method

private string removeNestedWhitespaces(char[] st)
{
    StringBuilder sb = new StringBuilder();
    int indx = 0, length = st.Length;
    while (indx < length)
    {
        sb.Append(st[indx]);
        indx++;
        while (indx < length && st[indx] == ' ')
            indx++;
        if(sb.Length > 1  && sb[0] != ' ')
            sb.Append(' ');
    }
    return sb.ToString();
}

use it like this:

string test = removeNestedWhitespaces("1 2 3  4    5".toCharArray());

Answer 2

It's much simpler than all that:

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

Answer 3

Old skool:

string oldText = "   1 2  3   4    5     ";
string newText = oldText
                    .Replace("  ", " " + (char)22 )
                    .Replace( (char)22 + " ", "" )
                    .Replace( (char)22 + "", "" );

Assert.That( newText, Is.EqualTo( " 1 2 3 4 5 " ) );

Answer 4

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 5

This is a shorter version, which should only be used if you are only doing this once, as it creates a new instance of the Regex class every time it is called.

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

If you are not too acquainted with regular expressions, here's a short explanation:

The {2,} makes the regex search for the character preceding it, and finds substrings between 2 and unlimited times.
The .Replace(temp, " ") replaces all matches in the string temp with a space.

If you want to use this multiple times, here is a better option, as it creates the regex IL at compile time:

Regex singleSpacify = new Regex(" {2,}", RegexOptions.Compiled);
temp = singleSpacify.Replace(temp, " ");

Answer 6

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 (" ");