Reduce multiple characters to one, in a string!

Adeel Chaudhry

Hello! Hope you all are doing great! Need suggestion of how to reduce multiple characters to 1! Example is as follows: We have a string str = "this is an example ! " we want to remove multiple space characters and want to have just single space instead! The number of spaces may be more than 200 in string! The result should be as follows: str = "this is an example ! " Any help/suggestion/guidence will certainly be appreciated!:)! Regards! Adeel --

Rob Graham

This should work:

string oneSpace = " ";
string twoSpaces = " ";
string str = "You left out any multiple spaces in your example";
string newStr = str.Replace(twoSpaces,oneSpace);

Luc Pattyn

Hi, since there may be more than 2 consecutive spaces, you need to iterate. This is how I do this:

string s="whatever with many spaces";
do {
int len=s.Length;
s=s.Replace(twoSpaces, oneSpace);
} while (s.Length<len);

For very long strings with many sequences of multiple spaces, it may be more economic to use a StringBuilder, and fill it in one pass using a bool that remembers whether last char added was a space or not. :)

Luc Pattyn [My Articles]

Adeel Chaudhry

it is not working!!!:)! extra spaces can be of any number!! and this will only replace 2 spaces with 1 what if we have 99 spaces?:)!

Adeel Chaudhry

:)! Thanks Luc, i guess i really have to learn to use stringbulder!:)! Thanks both of you!:)!

Guffa

Please don't end every sentence with an exclamation mark. Those are used for interjections and exclamations, not for ordinary sentences. An ordinary sentence is ended by a period. You can replace multiple spaces using a regular expresson: str = Regex.Replace(str, " {2,}", " ");

--- single minded; short sighted; long gone;

Adeel Chaudhry

:)actually they were used for exclamations and that is because working and learning new things of c# do make me happy.

Rob Graham

You are right, this would work better:

        string test = "this  string   has    multiple    spaces      .";
        StringBuilder sb = new StringBuilder(test);
        int l1 = sb.Length;
        int l2 = l1 +1;
        while (l1 != l2)
        {
            l1 = sb.Length;
            sb.Replace("  ", " ");
            l2 = sb.Length;
        }
        string result = sb.ToString();

PIEBALDconsult

I happen to have one here, one I wrote in C many years ago and then ported to C# a few years back, thanks for giving me a reason to revisit it. (Now I'll revisit my Split that honors quotes and escapes as well.) Usage: subject = the string to compress trash = list of characters to compress (usually " \b" -- SPACE and TAB) replacements = what to replace them with (usually " " -- SPACE) quotes = if you don't want compress within quotes, specify "\"" or "'" escapes = not often used, but if for instance trash contains "n" and subject contains "\n" and you don't want it replaced, specify "\\" for escapes and the "\n" will be preserved (quotes and escapes may be empty or null) advanced: two characters may be specified for replacements (and I've forgotten why I allow it) given trash="z" and replacements="xy" then subject="zzz" becomes "yyx" (rather than "x") example:

if ( args.Length > 0 )
{
System.Console.Write
(
"<" +
PIEBALD.Lib.LibStr.Compress ( args [ 0 ] , " \b" , " " , "'" , "\\" )
+ ">"
) ;
}

/**************************************************************************************************************/
/* Compress sequences of "trash" characters down to one */

    public static string
    Compress
    (
        string subject      ,
        string trash        ,
        string replacements ,
        string quotes       ,
        string escapes
    )
    {
        System.Text.StringBuilder result = new System.Text.StringBuilder ( subject.Length ) ;

        char prevch = '\\0' ;
        int  index  = 0    ;
        int  quo    = -1   ;
        int  quoon  = -1   ;
        int  escon  = -1   ;

        if ( quotes == null )
        {
            quotes = "" ;
        }

        if ( escapes == null )
        {
            escapes = "" ;
        }

        while ( index < subject.Length )
        {
            if ( ( escon = escapes.IndexOf ( prevch ) ) != -1 )
            {
                quoon = -1 ;
            }
            else
            {
                quoon = quotes.IndexOf ( subject \[ index \] ) ;
            }

            if ( quoon != -1 )
            {
                if ( qu

Adeel Chaudhry

:)! that is some re-usability!:)! the suggestion/guidence by Luc is proving to be great and actually bit simpler tooo ;) Thanks PIEBALDconsult :)

PIEBALDconsult

I don't like to write single-use library functions, the more flexibility the better in my opinion, but the RegularExpression solution may be our best bet.

Luc Pattyn

Sorry, but taking the trouble of using StringBuilder only makes sense if you succeed in avoiding unnecessary copy operations, hence StringBuilder.Replace is not my choice at all. Either you use String.Replace in a loop, or a one-pass populating StringBuilder. BTW your initial values for i1 and i2 are not needed if you test after the loop (do-while). :)

Luc Pattyn [My Articles]

PIEBALDconsult

If you're happy and you know it keep it to your own darn self.

AFSEKI

str = str.Replace(" ", " "); the first argument in str.Replace is a 2 white space characters ( press spacebar twice ) the second argument in str is a 1 white space character ( press spacebar once ) Sorry, but I had to explain these arguments ion details, they are not correctly shown after the message is posted. Hope this helps...