C # uses DataTable for group by data statistics

1, with two-layer cycle calculation, the precondition is that the data has been grouped by the column of the order.

DataTable dt = new DataTable ();
Dt. Columns.addrange (new datacolumn[] {new DataColumn ("name", typeof (String)),
New DataColumn ("Sex", typeof (String)),
New DataColumn ("Score", typeof (int))});
Dt. Rows.Add (new object[] {"Zhang San", "Male", 1});
Dt. Rows.Add (new object[] {"Zhang San", "Male", 4});
Dt. Rows.Add (new object[] {"John Doe", "Male", 100});
Dt. Rows.Add (new object[] {"John Doe", "female", 90});
Dt. Rows.Add (new object[] {"Harry", "Female", 77});
DataTable dtresult = dt. Clone ();
for (int i = 0; i < dt. Rows.Count; )
{
DataRow dr = Dtresult.newrow ();
String name = dt. rows[i]["Name"]. ToString ();
string sex = dt. rows[i]["Sex"]. ToString ();
dr["name"] = name;
dr["sex"] = sex;
int score = 0;
The inner layer also loops the same table and jumps out of the inner loop when different name is encountered
for (; i < dt. Rows.Count; )
{
if (name = = dt. rows[i]["Name"]. ToString () &&name = = dt. rows[i]["Sex"]. ToString ())
{
Score + = Convert.ToInt32 (dt. rows[i]["Score"]);
dr["score"] = score;
i++;
}
Else
{
Break
}
}
DTRESULT.ROWS.ADD (DR);

}

The data in Dtresult is the final result.

2, using the Compute method of the DataTable, the data in the DataTable is not ordered in advance.

DataTable dt = new DataTable ();
Dt. Columns.addrange (new datacolumn[] {new DataColumn ("name", typeof (String)),
New DataColumn ("Sex", typeof (String)),
New DataColumn ("Score", typeof (int))});
Dt. Rows.Add (new object[] {"Zhang San", "Male", 1});
Dt. Rows.Add (new object[] {"Zhang San", "Male", 4});
Dt. Rows.Add (new object[] {"John Doe", "Male", 100});
Dt. Rows.Add (new object[] {"John Doe", "female", 90});
Dt. Rows.Add (new object[] {"Harry", "Female", 77});
DataTable dtresult = dt. Clone ();
DataTable dtname = dt. Defaultview.totable (True, "name", "Sex");
for (int i = 0; i < DtName.Rows.Count; i++)
{
datarow[] rows = dt. Select ("Name=" + dtname.rows[i][0] + "' and sex= '" + dtname.rows[i][1] + "'");
Temp is used to store filtered data.
DataTable temp = Dtresult.clone ();
foreach (DataRow row in rows)
{
Temp. Rows.Add (row. ItemArray);
}

DataRow dr = Dtresult.newrow ();
Dr[0] = dtname.rows[i][0]. ToString ();
DR[1] = Temp.compute ("sum (score)", "");
DTRESULT.ROWS.ADD (DR);

}

3. Using LINQ to DataTable Group by

var query = from T in dt. AsEnumerable ()
Group T by new {T1 = t.field<string> (' name '), t2 = t.field<string> ("Sex")} into M
Select New
{
Name = M.key.t1,
Sex = M.key.t2,
Score = m.sum (n = n.field<decimal> ("score"))
};
if (query. ToList (). Count > 0)
{
Query. ToList (). ForEach (q =
{
Console.WriteLine (Q.name + "," + Q.sex + "," + Q.score);
});
}

C # uses DataTable for group by data statistics