C＃：数学函数

Question

i'm having a List<Double>

  List<Double>lst=new List<Double>{ 1.0,2.409,3.0}

I need to convert this list into a List<String>

So the result should contain

    { "1","2.409","3"}

in the result if the value does not have any floating points then need not add .0

Please help me to do this

Answer 1

If you're using .Net 3.5 you can use Linq:

lst.Select(n => String.Format("{0:0.###}", n));

Otherwise, you can do this the long way:

var output = new List<string>();

foreach (int number in lst)
{
    output.Add(String.Format("{0:0.###}", number));
}

Answer 2

Here is my take on this that doesn't rely on culture specific fraction separator, nor fixed amount of decimal places:

var result = lst.Select(
  n => { 
     double truncated = Math.Truncate(n);

     if(truncated == n) {
       return truncated.ToString("0");
     } else {
       return n.ToString();
     }
  }
);

Answer 3

        List<Double> lst=new List<Double>() { 1.0,2.409,3.0};
        List<string> output = lst.Select(val => val.ToString("0.######")).ToList();

should do what you want

Answer 4

List lst = new List { 1.0, 2.409, 3.0 };
List newlist =  lst.Select(val => val.ToString()).ToList();

Less writing....