How to Automatically Append New Rows to a Table in Excel Using VBA Without Duplicating Data?
Could someone explain I'm attempting to set up I'm performance testing and I'm optimizing some code but I'm optimizing some code but I'm trying to create a VBA macro that automatically appends new rows to an existing Excel table based on user input... However, I need to ensure that the new data does not duplicate any existing entries in the table. My current approach uses a simple `ListObject` to manage the table, but I'm running into issues with checking for duplicates properly. Here's the code I have so far: ```vba Sub AppendDataToTable() Dim ws As Worksheet Dim tbl As ListObject Dim newRow As ListRow Dim existingRow As ListRow Dim newValue As String Dim isDuplicate As Boolean Set ws = ThisWorkbook.Sheets("Data") Set tbl = ws.ListObjects("MyTable") newValue = InputBox("Enter new value:") isDuplicate = False ' Check for duplicates For Each existingRow In tbl.ListRows If existingRow.Range.Cells(1, 1).Value = newValue Then isDuplicate = True Exit For End If Next existingRow If Not isDuplicate Then Set newRow = tbl.ListRows.Add newRow.Range.Cells(1, 1).Value = newValue MsgBox "New row added successfully!" Else MsgBox "Duplicate entry found. No new row added." End If End Sub ``` When I run this macro and input a value that already exists in the table, it correctly identifies the duplicate and prevents the addition. However, when I enter a new value, it works as expected. The issue arises when the table is large (over 1000 rows); the performance significantly degrades, and it takes a long time to check for duplicates. I've tried using a `Dictionary` to store existing values but faced issues when trying to append new rows. Here’s a modified version that attempts to use a `Dictionary`: ```vba Dim existingValues As Object Set existingValues = CreateObject("Scripting.Dictionary") ' Populate dictionary For Each existingRow In tbl.ListRows existingValues.Add existingRow.Range.Cells(1, 1).Value, Nothing Next existingRow If Not existingValues.Exists(newValue) Then ' Add new row End If ``` Even with the dictionary, there’s a noticeable delay with larger datasets. I’m looking for efficient ways to handle this situation, particularly as the number of entries in the table grows. Any suggestions on optimizing the duplicate check or a different approach altogether would be greatly appreciated! How would you solve this? What's the best practice here? I'm using Vba 3.10 in this project. Any advice would be much appreciated. I'm using Vba 3.11 in this project. My development environment is Windows 11. What's the best practice here? I'm working in a macOS environment.