c# - Linq 直方图

Question

有没有办法用 linq 做一个分段直方图？我见过几个示例，您可以在其中计算特定对象的出现次数。是否可以创建一个基于 linq 的直方图来计算两个值之间的一系列对象的出现次数？

我不知道您将如何按一系列项目分组来创建直方图所需的桶？假设使用起始边界和宽度来创建范围。

您需要遍历数字数组并根据是否 <= Upper Bound 和 > Lower Bound 对每个数字进行分组。然后，您只需对每个组求和。我不知道如何按部分完成分组

Answer 1

是这样的吗？

        Random randF = new Random();
        List<double> nums = new List<double>();
        for (int i = 0; i < 100000; i++)
        {
            nums.Add(randF.NextDouble()*100);
        }

        double fromXF = 30;
        double toXF = 80;
        int groupCount = 10; // number of groups between values
        var histF = from i in nums
                    let groupKeyF = ((i-fromXF)/(toXF-fromXF)*groupCount) // even distribution of "groupCount" groups between fromXF and toXF, simple math, really
                    where groupKeyF >= 0 && groupKeyF < groupCount // only groups we want
                    let groupKey = (int)groupKeyF // clamp it to only group number
                    group i by groupKey into gr  // group it according to group number
                    orderby gr.Key
                    select new { Value = gr.Key, Count = gr.Count() };

        foreach (var item in histF)
        {
            Console.WriteLine("Group number: " + item.Value + ", Count: " + item.Count);
        }