Parse string for doubles

Question

I need to parse the string for the doubles it contains and store it in a list of doubles so later I can take the values and store them in a variable.

You can see on the picture in the richtextbox I have the string content now I tried to parse it like this

public void GetAll()
{       
   List<double> doubles = new List<double>();
   MatchCollection matches = Regex.Matches(buff, @"(([-]|[+])?\d+[.]\d+)");         
   foreach (Match match in matches)
   {
       string val = match.Groups[1].Value;
       doubles.Add(double.Parse(val));        
   }
}

and it doesnt store the doubles in the list.
I need them stored in order they show up doubles[0] = value of vv_in, doubles[1] = values of vv_out and so on.

Answer 1

You want to store the double that might be at the end of the strings? I'd use this approach:

List<double> doubles = new List<double>();
string[] lines = yourTextBox.Lines;
foreach(string line in lines)
{
    int lastSpaceIndex = line.LastIndexOf(' ');
    string doubleToken = line.Substring(++lastSpaceIndex);
    double d;
    if(double.TryParse(doubleToken, out d))
        doubles.Add(d);
}

Answer 2

Can't really test it without your data, but this is worth a try:

var doubles = from line in buff.Split(new[] { Environment.NewLine }, StringSplitOptions.RemoveEmptyEntries)
              from item in line.Split(new[] { ' ' }, StringSplitOptions.RemoveEmptyEntries)
              where double.TryParse(item, out var _)
              select double.Parse(item);

As mentioned in the comments, this uses discards, which are a C# 7 feature.

Answer 3

Actually your code works almost fine. The only thing you have to tune, it that Parse needs to take the culture into account. And I changed your regex so it can cope with optional decimal digits:

List<double> doubles = new List<double>();

MatchCollection matches = Regex.Matches(buff, @"(([-]|[+])?\d+(.\d+)?)");  
foreach (Match match in matches)
{
    string val = match.Groups[1].Value;
    doubles.Add(double.Parse(val, System.Globalization.CultureInfo.InvariantCulture));

}

Answer 4

You should first split your values into single lines and then every line at the whitespaces. At last try to parse the second part of the obtained array into a double:

public void GetAll()
{

   List<double> doubles = new List<double>();
   foreach(var line in buff.Split('\n')
   {
       var parts = line.Split();
       if(parts.Length == 3)
       {
           double d;
           if(double.TryParse(parts[2], out d)
               doubles.Add(d);
       }
    }
}