IsDouble

Returns true if the given string can be parsed into a double, false otherwise.

• Return the result of calling Double.TryParse() with NymberStyles.Float for the given num string.

using System.Globalization;

public static partial class _30s 
{
  public static bool IsDouble(string num) 
  {
    Double _ = 0.0;
    return Double.TryParse(num, NumberStyles.Float, NumberFormatInfo.CurrentInfo, out _);
  }
}

_30s.IsDouble("2"); // true
_30s.IsDouble("hi"); // false