LINQ版本，用于计算数组中相邻元素的和积 [英] LINQ version of calculating sum product of adjacent elements in an array

问题描述

我正在寻找一种在LINQ中执行以下操作的方法(它基本上是一个sumproduct，其中同一数组包含 n 和 n + 1 索引，显然数组长度始终为 2 * n ).

I am looking for a way to do the following in LINQ (it is basically a sumproduct where the same array contains both operands of the product at n and n + 1 indices, obviously the array length is always 2 * n).

int[] input = { -3, 26, -2, 19, 2, 19, 3, 29, 1, 48 };

// sum product
double result = 0;
for (int i = 0; i < input.Length; i += 2)
     result += input[i] * input[i + 1];

// result = 57

// linq version of calculating resultPrice ???

如何使用LINQ做到这一点(优雅)?

How can I do this (elegantly) with LINQ?

推荐答案

 var result = Enumerable.Range(0, input.Length/2)
                          .Select(i => input[i*2] * input[i*2 + 1]).Sum();

这应该足够了.以下是 dotNetFiddle 中的示例.

This should be enough. Here example in dotNetFiddle.

此代码几乎是以下内容的镜像:

This code is pretty much mirror of:

for (int i = 0; i < input.Length/2; i++)
     result += input[i*2] * input[i*2 + 1];

与循环完全相同，但是没有循环的步骤 +2 ，而是具有步骤 +1 和循环持续时间 ArrayItems/2 ，然后从 input [i * 2] * input [i * 2 + 1]

which is doing the exact same thing as your loop, but instead of step +2 of your loop you have step +1 and loop duration ArrayItems/2 and you make sum of elements from input[i*2] * input[i*2 + 1]

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