How can I parse only the float number from the string?

Question

foreach (object item in listBox1.SelectedItems)
{
    string curItem = item.ToString();
    var parts = curItem.Split("{}XY=, ".ToCharArray(), StringSplitOptions.RemoveEmptyEntries);
    var xCoord = float.Parse(parts[0]);
    var yCoord = float.Parse(parts[1]);
    var point = new PointF(xCoord, yCoord);
    CloudEnteringAlert.pointtocolor.Add(point);
    pictureBox1.Invalidate();
}

The curItem variable contains value like that: Cloud detected at: 0.9174312 Kilometers from the coast.

I want to get only the 0.9174312 from value and set to be in the variable xCoord. The problem is that the way it is doing the parsing now i'm getting error:

Input string was not in a correct format

The index should not be zero, I guess. How can I get only the float number from the string?

And this strings formats for now are the same each time:

First part: Cloud detected at: Second part: 0.9174312 and Last part: Kilometers from the coast.

But maybe in the future I will change the string format so i need that in any place the float number will be in the middle last or start of the string to get only the float number.

you should get string between : and Kilometers then trim it. — Kamran Shahid, Sep 15 '14 at 05:56
I tried float.Parse("0.9174312") it is converting fine. May be your string having space. Try this parts[0].Trim() . — SeeTheC, Sep 15 '14 at 05:58
Check the following link [Link](http://stackoverflow.com/questions/1014535/float-parse-doesnt-work-the-way-i-wanted) — Srikanth, Sep 15 '14 at 06:01
@SeeTheC: On my machine `float.Parse("0.9174312")` would yield `9174312`. Ignoring culture when parsing numbers is never a good idea. — Joey, Sep 15 '14 at 06:12

score 5 · Accepted Answer · answered Sep 15 '14 at 05:58

5

Consider using regular expressions.

var match = Regex.Match(val, @"([-+]?[0-9]*\.?[0-9]+)");
if (match.Success)
  xCoord = Convert.ToSingle(match.Groups[1].Value);

answered Sep 15 '14 at 05:58

Andrey Korneyev

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You should probably give `ToSingle` the correct culture, too. – Joey Sep 15 '14 at 06:12

score 4 · Answer 2 · answered Sep 15 '14 at 06:03

You can simply extract the float from the string by using Regular Expressions:

string xCoord = Regex.Match(curItem, @"[-+]?[0-9]*\.?[0-9]+").Groups[1].Value;

After that, you can parse it to a float.

More info about regular expressions can be found here, or you could take a look at the Regex class page from MSDN.

score 2 · Answer 3 · answered Sep 15 '14 at 06:06

try this

 foreach (object item in listBox1.SelectedItems)
        {
            string curItem = item.ToString();
            var parts = curItem.Split("{}XY=, ".ToCharArray(), StringSplitOptions.RemoveEmptyEntries);
            var xCoord = CultureCheck(parts[0]);
            var yCoord = CultureCheck(parts[1]);
            var point = new PointF(xCoord, yCoord);
            CloudEnteringAlert.pointtocolor.Add(point);
            pictureBox1.Invalidate();
        }       


    private double CultureCheck(string input)
    {
        CultureInfo ci = (CultureInfo)CultureInfo.CurrentCulture.Clone();
        ci.NumberFormat.CurrencyDecimalSeparator = ".";
       return double.Parse(input, NumberStyles.Any, ci);
    }

How can I parse only the float number from the string?

3 Answers3

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