regex - Regular expression replace in C#

Question

I'm fairly new to using regular expressions, and, based on a few tutorials I've read, I'm unable to get this step in my Regex.Replace formatted properly.

Here's the scenario I'm working on... When I pull my data from the listbox, I want to format it into a CSV like format, and then save the file. Is using the Replace option an ideal solution for this scenario?

Before the regular expression formatting example.

FirstName LastName Salary    Position
-------------------------------------
John      Smith    $100,000.00  M

Proposed format after regular expression replace

John Smith,100000,M

Current formatting status output:

John,Smith,100000,M

*Note - is there a way I can replace the first comma with a whitespace?

Snippet of my code

using(var fs = new FileStream(filepath, FileMode.OpenOrCreate, FileAccess.Write))
{
    using(var sw = new StreamWriter(fs))
    {
        foreach (string stw in listBox1.Items)
        {
            StringBuilder sb = new StringBuilder();
            sb.AppendLine(stw);

            //Piecing the list back to the original format
            sb_trim = Regex.Replace(stw, @"[$,]", "");
            sb_trim = Regex.Replace(sb_trim, @"[.][0-9]+", "");
            sb_trim = Regex.Replace(sb_trim, @"s", ",");
            sw.WriteLine(sb_trim);
        }
    }
}

question from:https://stackoverflow.com/questions/16117043/regular-expression-replace-in-c-sharp

Answer 1

You can do it this with two replace's

//let stw be "John Smith $100,000.00 M"

sb_trim = Regex.Replace(stw, @"s+$|s+(?=w+$)", ",");
//sb_trim becomes "John Smith,100,000.00,M"

sb_trim = Regex.Replace(sb_trim, @"(?<=d),(?=d)|[.]0+(?=,)", "");
//sb_trim becomes "John Smith,100000,M"

sw.WriteLine(sb_trim);