Run VBA script from R

Question

I have to manage a workflow involving R-scripts and VBA-code. I would like to run the process in R (where most of my code is) and now and then to call VBA-code for specific calculation.

I would prepare the inputs for VBA in R, write somewhere the results (.csv, database) and then use the results in the rest of the R-script.

The best would be of course to move the whole code into R but this is for now not possible. The VBA-code is fairly complex. Translating this into R will be a challenging long-term task.

Is there any possibility to manage in R such a work-flow?

Answer 1

1. Write a VBscript wrapper that calls your VBA. See Way to run Excel macros from command line or batch file?

2. Run your VBscript via R's system or shell functions.

Answer 2

Here's a method which doesn't require a VBscript wrapper. You'll need to install the RDCOMClient package

library(RDCOMClient)

# Open a specific workbook in Excel:
xlApp <- COMCreate("Excel.Application")
xlWbk <- xlApp$Workbooks()$Open("C:\\Temp\\macro_template.xlsm")

# this line of code might be necessary if you want to see your spreadsheet:
xlApp[['Visible']] <- TRUE 

# Run the macro called "MyMacro":
xlApp$Run("MyMacro")

# Close the workbook and quit the app:
xlWbk$Close(FALSE)
xlApp$Quit()

# Release resources:
rm(xlWbk, xlApp)
gc()