根据另一列的值汇总DataTable中的列值

Question

I have a DataTable, like this:

Amount | Count
-----------------------
20.0   | 2
42.0   | 1
78.0   | 5
91.0   | 2

I'd like to sum up the Count column, based on what's in the Amount column.

I want to find the sum of Count for all Amount between 0 - 50 and 51-100, which would be 3 and 7 in this example.

Is there a way to quickly get that data?

Here's what I have currently:

foreach (int min in ranges)
{
    int max = min + 50;
    int count = 0;

    foreach (DataRow dr in dt)
    {
        if (dr["Amount"] > min && dr["Amount"] < max)
            count += dr["Count"];
    }
}

I'm looking for a more elegant solution

Answer 1

A good link for learning Linq is 101 Linq samples . The following piece of code should give you a good starting point though it creates ranges from 0 to <50, 50 to <100 and so on. It assumes that the ranges do have regular intervals.

var dt = new DataTable();
dt.Columns.Add("Amount", typeof(int));
dt.Columns.Add("Count", typeof(int));
dt.Rows.Add(20, 2);
dt.Rows.Add(42, 1);
dt.Rows.Add(78, 5);
dt.Rows.Add(91, 2);
var result = from DataRow x in dt.Rows
                group x by ((int)x["Amount"]) / 50 into grp 
                select new {LowerBoundIncl = grp.Key * 50, 
                        UpperBoundExcl = (grp.Key + 1) * 50, 
                        TotalCount = grp.Sum(y => (int) y["Count"])};

Hope this helps.