I have a datatable, dtFoo, and would like to get a count of the rows that meet a certain criteria.
EDIT: This data is not stored in a database, so using SQL is not an option.
In the past, I've used the following two methods to accomplish this:
Method 1
int numberOfRecords = 0;
DataRow[] rows;
rows = dtFoo.Select("IsActive = 'Y'");
numberOfRecords = rows.Length;
Console.WriteLine("Count: " + numberOfRecords.ToString());
Method 2
int numberOfRecords = 0;
foreach (DataRow row in dtFoo.Rows)
{
if (row["IsActive"].ToString() == "Y")
{
numberOfRecords++;
}
}
Console.WriteLine("Count: " + numberOfRecords.ToString());
My shop is trying to standardize on a few things and this is one issue that has come up. I'm wondering which of these methods is best in terms of performance (and why!), as well as which is most commonly used.
Also, are there better ways to achieve the desired results?
One easy way to accomplish this is combining what was posted in the original post into a single statement:
int numberOfRecords = dtFoo.Select("IsActive = 'Y'").Length;
Another way to accomplish this is using Linq methods:
int numberOfRecords = dtFoo.AsEnumerable().Where(x => x["IsActive"].ToString() == "Y").ToList().Count;
Note this requires including System.Linq
.
int numberOfRecords = DTb.Rows.Count;
int numberOfColumns = DTb.Columns.Count;
object count =dtFoo.Compute("count(IsActive)", "IsActive='Y'");
Not sure if this is faster, but at least it's shorter :)
int rows = new DataView(dtFoo, "IsActive = 'Y'", "IsActive",
DataViewRowState.CurrentRows).Table.Rows.Count;
Try this
int numberOfRecords = dtFoo.Select("IsActive = 'Y'").Count<DataRow>();
Console.WriteLine("Count: " + numberOfRecords.ToString());
int row_count = dt.Rows.Count;
If the data is stored in a database it will be faster to send the query to the database instead of getting all data and query it in memory.
A third way to do it will be linq to datasets, but i doubt any of these 3 methods differ much in performance.
int numberOfRecords = 0;
numberOfRecords = dtFoo.Select().Length;
MessageBox.Show(numberOfRecords.ToString());
Source: Stackoverflow.com