Re: Reduce multiple characters to one, in a string! - C# Discussion Boards

Re: Reduce multiple characters to one, in a string!

6-May-07 4:17

! Thanks Luc, i guess i really have to learn to use stringbulder! Smile | :)

! Thanks both of you! Smile | :)

Rob Graham6-May-07 4:40

Rob Graham

6-May-07 4:40

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();

Re: Reduce multiple characters to one, in a string!

Luc Pattyn6-May-07 5:25

Luc Pattyn

6-May-07 5:25

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).

Smile | :)

Luc Pattyn

[My Articles]

Re: Reduce multiple characters to one, in a string!

Adeel Chaudhry6-May-07 4:15

Re: Reduce multiple characters to one, in a string!

6-May-07 4:15

it is not working!!! Smile | :)

! extra spaces can be of any number!! and this will only replace 2 spaces with 1 what if we have 99 spaces? Smile | :)

Guffa6-May-07 4:25

Guffa

6-May-07 4:25

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;

Re: Reduce multiple characters to one, in a string!

Adeel Chaudhry6-May-07 4:36

Re: Reduce multiple characters to one, in a string!

6-May-07 4:36

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

PIEBALDconsult6-May-07 6:52

Re: Reduce multiple characters to one, in a string!

6-May-07 6:52

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

PIEBALDconsult6-May-07 4:41

Re: Reduce multiple characters to one, in a string!

6-May-07 4:41

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 ( quo == -1 )
                    {
                        quo = quoon ;
                    }
                    else
                    {
                        if ( quo == quoon )
                        {
                            quo = -1 ;
                        }
                    }
                }

                prevch = subject [ index ] ;

                if ( ( quo == -1 ) && ( trash.IndexOf ( subject [ index ] ) != -1 ) )
                {
                    if ( ( index == subject.Length-1 ) || ( trash.IndexOf ( subject [ index+1 ] ) == -1 ) )
                    {
                        result.Append ( replacements [ 0 ] ) ;
                    }
                    else
                    {
                        if ( replacements.Length > 1 )
                        {
                            result.Append ( replacements [ 1 ] ) ;
                        }
                    }

                    index++ ;
                }
                else
                {
                    result.Append ( subject [ index++ ] ) ;
                }
            }

            return ( result.ToString() ) ;
        }

Adeel Chaudhry6-May-07 4:54

Re: Reduce multiple characters to one, in a string!

6-May-07 4:54

! that is some re-usability! Smile | :)

! the suggestion/guidence by Luc is proving to be great and actually bit simpler tooo Wink | ;)

Thanks PIEBALDconsult Smile | :)

PIEBALDconsult6-May-07 4:57

Re: Reduce multiple characters to one, in a string!

6-May-07 4:57

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.

AFSEKI7-May-07 2:09

AFSEKI

7-May-07 2:09

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...

Treeview challenge

Rick van Woudenberg6-May-07 3:07

Rick van Woudenberg

6-May-07 3:07

Dear all,

I have a treeview which I populate from a postgres database. This all works fine, and I'm using the following code :

            DataRow newRow = dt.NewRow();<br />
            dt.Columns.Add("Resources", typeof(System.String));<br />
<br />
            if (dt.Rows.Count > 0)<br />
            {<br />
                treeView1.BeginUpdate();<br />
                foreach (DataRow r in dt.Rows)<br />
                {<br />
                    treeView1.Nodes.Add(new TreeNode(r["res_lastname"].ToString()));<br />
                }<br />
                treeView1.EndUpdate();<br />
            }

Well, I'm not grabbing the data from the database directly but rather through a dataset.
I can add as many rows as I like, just by putting an extra line in , like this :

treeView1.Nodes.Add(new TreeNode(r["res_lastname"].ToString()));<br />
treeView1.Nodes.Add(new TreeNode(r["res_firstname"].ToString()));

Lastname and Firstname show up in the treeview below eachother :

-- Lastname
-- Firstname

Is there a way to show them right next to eachother , like this :

-- Lastname, Firstname

kind regards,

Rick

Arun.Immanuel6-May-07 3:54

Arun.Immanuel

6-May-07 3:54

Rick van Woudenberg wrote:
treeView1.Nodes.Add(new TreeNode(r["res_lastname"].ToString()));
treeView1.Nodes.Add(new TreeNode(r["res_firstname"].ToString()));

Have you tried this?

treeView1.Nodes.Add(new TreeNode(r["res_lastname"].ToString() + "," + r["res_firstname"].ToString()));

Regards,
Arun Kumar.A

Rick van Woudenberg6-May-07 4:23

Rick van Woudenberg

6-May-07 4:23

I just did and it works perfect. I need a vacation, how could I miss that ? :-S

Thank you so much for your help and quick input.

Cheers !

PIEBALDconsult6-May-07 5:03

6-May-07 5:03

No, you should query the fullname like
res_fullname=res_lastname+' '+res_firstname
and then use
treeView1.Nodes.Add(new TreeNode(r["res_fullname"].ToString()

Rick van Woudenberg6-May-07 9:31

Rick van Woudenberg

6-May-07 9:31

Thank you for your reply, and your solutions seems to work as well.
Is there a significant difference in the two approaches, or is it just a matter of taste ?

Cheers ?

PIEBALDconsult6-May-07 18:18

PlugIns - Preventing Malicious Code...

6-May-07 18:18

That was a joke, notice the smiley? (I guess I should have put it inside the message.)

Shy Agam6-May-07 2:49

Shy Agam

6-May-07 2:49

Hello experts,

I'm working on a system which would be able to dinamically load all kinds of multiplayer games.
In order for the system to know how to handle any game, I set up some ground rules using an abstract class named GameEngine.
Among other stuff, it contains an abstract ProcessMessage() method.

At first I thought of loading DLLs from a special folder, and analyzing every class which inherits GameEngine.
But then came another thought into my mind...
What if someone, instead of implementing a game, inherits GameEngine and puts down malicious code into ProcessMessage()?

My first solution is not to read DLLs from a directory, but to read only a DLL that I will code... Whenever I want to add another game, I would update the DLL...
However, this prevents other programmers from adding games to my program...

What can I do?

Thanks in advance,
Shy.

Re: PlugIns - Preventing Malicious Code...

PIEBALDconsult6-May-07 18:20