List<int> 中 int 的总和范围

问题描述

我认为这将是微不足道的，但我不知道该怎么做.我有一个 List<int>，我想对一系列数字求和.

I reckon this will be quite trivial but I can't work out how to do it. I have a List<int> and I want to sum a range of the numbers.

假设我的清单是:

var list = new List<int>()
{
    1, 2, 3, 4
};

如何获得前 3 个对象的总和?结果是 6.我尝试使用 Enumerable.Range 但无法让它工作，不确定这是否是最好的方法.

How would I get the sum of the first 3 objects? The result being 6. I tried using Enumerable.Range but couldn't get it to work, not sure if that's the best way of going about it.

不做:

int sum = list[0] + list[1] + list[2];

推荐答案

您可以使用 采取 &总和:

You can accomplish this by using Take & Sum:

var list = new List<int>()
{
    1, 2, 3, 4
};

// 1 + 2 + 3
int sum = list.Take(3).Sum(); // Result: 6

如果您想对从其他地方开始的范围求和，可以使用 跳过:

If you want to sum a range beginning elsewhere, you can use Skip:

var list = new List<int>()
{
    1, 2, 3, 4
};

// 3 + 4
int sum = list.Skip(2).Take(2).Sum(); // Result: 7

或者，使用 OrderBy 重新排序您的列表a> 或 OrderByDescending 然后求和:

Or, reorder your list using OrderBy or OrderByDescending and then sum:

var list = new List<int>()
{
    1, 2, 3, 4
};

// 3 + 4
int sum = list.OrderByDescending(x => x).Take(2).Sum(); // Result: 7

如您所见，有多种方法可以完成此任务(或相关任务).请参阅 Take、Sum, 跳过, OrderBy &OrderByDescending 文档了解更多信息.

As you can see, there are a number of ways to accomplish this task (or related tasks). See Take, Sum, Skip, OrderBy & OrderByDescending documentation for further information.

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