c# linq, sum distinct values by index

Question

I have multiple List with multiple values that may or may not have the same number of items.. I need to add up only the numbers for a distinct name by index..

heres some code to help explain...

    public static List<p> pList= new List<p>();
    public class p
    {
        public string name;
        public double sum;
        public List<double> ip;
    }

So, I have class "p", as a list.. some of the names in class "p" will be same and some different..

I need to sum the values in "ip" by index for only the class "p" that has the same name..

Data Example..

name = a, sum = 10, ip = {2,2,2,2,2}    
name = a, sum = 10, ip = {0,0,5,5}    
name = a, sum = 5, ip = {0,0,5}    
name = b, sum = 20, ip = {0,20}    
name = b, sum = 10, ip = {10}    

Result..

name = a, sum = 25, ip = {2,2,12,7,2}    
name = b, sum = 30, ip = {10,20}    

Below is the code I have already written..

List<p> distinctmerge = pList
                         .GroupBy(t => t.name)
                         .Select(g => new p
                         {
                             name = g.Select(a => a.name).FirstOrDefault(),
                             sum = g.Sum(a => a.sum),
                             ip = new List<double>() { 1, 2, 3 }
                         }).ToList();

The part I cant figure out is here..

ip = new List<double>() { 1, 2, 3 }

Answer 1

您可以通过以下方式总结IP列表：

 ip = Enumerable.Range(0, g.Select(a => a.ip.Length).Max()).Select(idx => g.Select(a => a.ip.ElementAtOrDefault(idx)).Sum()).ToList() 

Answer 2

It can be done using SelectMany and GroupBy :

        List<p> distinctmerge = pList
            .GroupBy(t => t.name)
            .Select(g => new p
            {
                name = g.Select(a => a.name).FirstOrDefault(),
                sum = g.Sum(a => a.sum),
                ip = g.SelectMany(a => a.ip.Select((e, i) => new { e, i }))
                      .GroupBy(a => a.i)
                      .OrderBy(a => a.Key)
                      .Select(a => a.Sum(e => e.e))
                      .ToList()
            }).ToList();