For Each Row in DataTable taking over an hour to run

My datatable has about 53000 rows and 13 columns. One of the columns is an ID and I would like to remove invalid IDs and remain with valid IDs that have 8 string characters.
Manually, I have determined that the invalid IDs are about 200.
How can I loop through the rows to find and remove these invalid IDs in the shortest time possible?
I want to remain with the valid IDs in a datatable so I can perform other actions on them. The invalid IDs will be emailed to a system admin for remediation.

Thanks for the help

Hi @T.S ,

Could you let us know if you would want to Remove/Update the ID column value or remove the whole row consisting of that invalid ID ?

I would like to remove the whole row consisting of the invalid ID.


You can use LINQ Quirey to remove it, If you want to read more than 10,000 rows I recommend using LINQ Quirey.

If you need the LINQ Quirey please provide sample input so we can help you.

Chethan P

@T.S ,

In that case, maybe we can check with the below Expression on finding the Invalid IDs :

invalidIds = DT.AsEnumerable.Where(Function(x)Not(x("ID Column").ToString.Trim.Length=8)).Select(Function(x)x("ID Column").ToString).ToArray

Here, invalidIds is a variable of type Array of String and DT is your Input Datatable variable.

For Removing the Invalid ID Rows in DT, We can check with the below :

UpdatedDT = DT.AsEnumerable.Where(Function(x)x("ID Column").ToString.Trim.Length=8).CopyToDatatable

Here, UpdatedDT is of the type Datatable. You could use the same datatable as well.

Sample input will look like the image.
I am only interested in the rows where column 13 has only 8 characters.


We do feel that with a combination of Regex / StringCheck and LINQ we can do like

Assign Activity (valid Rows DT)
dtValidRows =

(From d In yourDataTableVar.AsEnumerable()
Where Not isNothing(d("YourColName"))
Let n = d("YourColName").toString.Trim
Where Not String.IsNullOrEmpty(n)
Where n.Length.Equals(8) 
Where System.Text.RegularExpressions.Regex.isMatch(n,"[A-Za-z0-9]+")
Select r = d).CopyToDataTable

Assign Activity (invalid Rows DT)
dtInvalidRows =

yourDataTableVar.AsEnumerable.Except(dtValidRows.AsEnumerable, DataRowComparer.Default ).CopyToDataTable

Yes, but letter and digit only

we adapted to:

I am still new to studio, :sweat_smile:here are the errors I get

we corrected the LINQ as a closing bracket was missplaced
Provided LINQ is in VB.Net Language

Could it be the case that your project is set to C#?

My project is in VB.Net.
The LINQ works however it outputs only one record, yet I am expecting over 50,000.
How can I remedy this?

Can you share some details about the processed data e.g. Excel / CSV or a screenshot from the immediate panel?

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