Question

EDIT : I had tried these two ways before –

List<double> doubleList =
stringList.ConvertAll(x => (double)x);

List<double> doubleList =
stringList.Select(x =>
(double)x).ToList();

and got this error:

Cannot convert type ‘string’ to’double’

I read about something similiar that convert ints to doubles…but I have List of strings which I need to convert to List of doubles and the ConvertAll() does not work neither the Select extension method. Can anyone please help me out.

Answer 1

The select method ought to work if you are using .NET 3.5 or newer:

List<double> result = l.Select(x => double.Parse(x)).ToList();

Here is some example code:

List<string> l = new List<string> { (0.1).ToString(), (1.5).ToString() };
List<double> result = l.Select(x => double.Parse(x)).ToList();
foreach (double x in result)
{
    Console.WriteLine(x);
}

Result:

0,1
1,5

One thing to be aware of is which culture you are using to parse the strings. You might want to use the Parse overload that takes a culture and use CultureInfo.InvariantCulture for example.