如何总结重复元件的值在阵列

Question

我有两个阵列：

string[] fruit = { "apple", "banana", "lemon", "apple", "lemon" }; 
int[] quantity = { 2,   4,  1,  2,  2 }; 

第二个具有第一个相同长度，而整数各自果的量。

我想创建这两个数组：

totalefruit = { "apple", "banana", "lemon" }; 
totalquantity = {4,   4,  3} 

Answer 1

试试这个：

string[] fruit = { "apple", "banana", "lemon", "apple", "lemon" }; 
int[] quantity = { 2, 4, 1, 2, 2 }; 

var result = 
    fruit 
     .Zip(quantity, (f, q) => new { f, q }) 
     .GroupBy(x => x.f, x => x.q) 
     .Select(x => new { Fruit = x.Key, Quantity = x.Sum() }) 
     .ToArray(); 

var totalefruit = result.Select(x => x.Fruit).ToArray(); 
var totalquantity = result.Select(x => x.Quantity).ToArray(); 

result看起来是这样的：

Answer 2

你可以使用Zip和查找：

var fruitQuantityLookup = fruit 
    .Zip(quantity, (f, q) => new { Fruit = f, Quantity = q }) 
    .ToLookup(x => x.Fruit, x => x.Quantity); 
string[] totalefruit = fruitQuantityLookup.Select(fq => fq.Key).ToArray(); 
int[] totalquantity = fruitQuantityLookup.Select(fq => fq.Sum()).ToArray();