选择自定义类型列表的一部分到新的类型为double的列表中

Question

I have a custom list of type 'Sales' called SalesList. The class Sales has a fields, of type double and datetimes. The field I am interested in is of type double and call Value_USD. The list contains approx. 10,000 items at runtime.

What I would like to do is select a section of SalesList. Say all the elements from 150 to 350 and select the Value_USD into a new List of type double.

I know I could use GetRange if the lists were of the same type.

Answer 1

尝试这个：

List<double> values = SalesList.Skip(149).Take(200).Select(s => s.Value_USD).ToList()

Answer 2

Use a foreach loop to loop through your sales list and add the double value to other list like below

List<double> dlst = new List<Double>();
int counter = 0;
foreach(Sales s in SalesList)
{
  counter++;
  if(counter >= 150 && counter <= 350)
  dlst.Add(s.Value_USD);
}