Excel spreadsheets can be imported into XDF files using rxImport via the Excel ODBC interface. Given that the Excel ODBC driver is installed and configured on Windows, an example of code for importing a worksheet "Sheet1" from workbook "C:/Data/ODBCTest.xlsx" would be:
#Define ODBC connection string.
connectionStr <- "Driver={Microsoft Excel Driver (*.xls, *.xlsx, *.xlsm, *.xlsb)};DriverId=790;Dbq=C:/Data/ODBCTest.xlsx;DefaultDir=c:/Data;"
#Define ODBC query into workbook. The worksheet name must be followed by '$' and enclosed in [].
testExcel = "SELECT * FROM [Sheet1$]"
#Define ODBC data source for the import using the query and connection string.
excelDS<- RxOdbcData(sqlQuery = testExcel, connectionString=connectionStr)
#Define input workbook and output xdf file.
excelDS_XDF<- RxXdfData("testFromExcel.xdf")
#Import the workbook into the XDF
rxImport(excelDS, excelDS_XDF, overwrite=TRUE)