VBA: How to efficiently handle large datasets without running into 'Out of Memory' errors?
I'm writing unit tests and I'm relatively new to this, so bear with me. I'm working on an Excel VBA project that involves processing a large dataset, approximately 1 million rows, stored in a worksheet. While trying to loop through the data to perform calculations, I'm frequently working with 'Out of Memory' errors, especially when using arrays to store data temporarily. I've tried breaking the dataset into smaller chunks and processing them individually, but this approach is still causing performance optimization and delays. Below is a simplified version of my code: ```vba Sub ProcessLargeDataset() Dim ws As Worksheet Dim dataRange As Range Dim rowCount As Long Dim i As Long Set ws = ThisWorkbook.Sheets("Data") rowCount = ws.Cells(ws.Rows.Count, 1).End(xlUp).Row Set dataRange = ws.Range("A2:A" & rowCount) Dim dataArr() As Variant dataArr = dataRange.Value For i = LBound(dataArr, 1) To UBound(dataArr, 1) ' Perform some calculations dataArr(i, 1) = dataArr(i, 1) * 1.1 ' Just an example calculation Next i dataRange.Value = dataArr End Sub ``` This code processes the entire dataset in one go, but as the dataset grows larger, I find that it's not scalable for my needs. I've also considered using `Variant` arrays, but that doesn't seem to alleviate the memory issues. Is there a more efficient way to handle such large datasets in VBA? Are there specific techniques, such as using `Range.Value2` instead of `Range.Value`, or alternatives to looping through each row that could help? Any guidance on best practices for working with large datasets in VBA would be greatly appreciated. For context: I'm using Vba on Windows. Has anyone else encountered this? Hoping someone can shed some light on this.