从字符串列表中求和并创建字典

Question

I want to calculate and sum all values from a sorted list of string like that

List<string> sortedList = new List<string>();
//name, number, weight
sortedList.Add("A,5,1");
sortedList.Add("A,3,2");
sortedList.Add("B,4,1");
sortedList.Add("B,6,2");

sortedList.Sort();

Input: (List l)

Output: (List<Dicionary<string,int>> result):

A ( (5*1)+ ( 3*2) )
B ( (4*1) + (6*2) )

---

new List of dictionary <string, int>

1 - dic["A" , 11]
2 - dic["B" , 16]

Answer 1

Using linq you can do this.

Dictionary<string, int> r = sortedList.Select(x => x.Split(','))
    .GroupBy(x => x[0])
    .ToDictionary(x => x.Key, x => x.Sum(y => int.Parse(y[1])*int.Parse(y[2])));

First split all the string by , . then group them by first element of array. then convert them into dictionary. first element is key. and the value is sum of element2*element3

Answer 2

First you need to split string so you can get multiplication and key. You can split using Split method. Also, you need to skip first element after splitting.

var multArray = sortedList.Select (x=>int.Parse (x.Split(',')[1])*int.Parse (x.Split(',')[2]));
var keyArray = sortedList.Select (x=>x.Split(',')[0]);

multArray is array with sums, and keyarray is array with keys. Then you need populate dictionary.

for (int i = 0; i  < keyArray.Count(); i ++) 
{
    if (dictionary.ContainsKey (keyArray[i])) 
    { 
        dictionary[keyArray[i]] += multArray [i];
    } 
    else
    {
        dictionary.Add (keyArray[i], multArray [i]);
    }
}