openxlsx not able to read from .xlsx file in R

Question

I am trying to read value from a .xlsx file using openxlsx package in R. In simple words, I need to write a row of data, which then p

Answer 1

?read.xlsx

Formulae written using writeFormula to a Workbook object will not get picked up by read.xlsx(). This is because only the formula is written and left to be evaluated when the file is opened in Excel. Opening, saving and closing the file with Excel will resolve this.

So the file needs to be opened in Excel and then saved, I can verify that this does work. However this may not be suitable for you.

XLConnect seems to have the desired functionality

# rjava can run out of memory sometimes, this can help.
options(java.parameters = "-Xmx1G")
library(XLConnect)

file_path = "test.xlsx"

input_row <- c("c", 5)

wb <- loadWorkbook(file_path, create=F)
writeWorksheet(wb, 1, startRow = 1, startCol = 1, data = data.frame(input_row))
setForceFormulaRecalculation(wb, 1, TRUE)
saveWorkbook(wb)

# checking
wb <- loadWorkbook(file_path, create=F)
readWorksheet(wb, 1)

Answer 2

The file https://cran.r-project.org/web/packages/openxlsx/openxlsx.pdf says

Workbook object will not get picked up by read.xlsx(). This is because only the formula is written and left to be evaluated when the file is opened in Excel. Opening, saving and closing the file with Excel will resolve this. So if you are using windows then save following file vbs file to for example opensaveexcel.vbs

Set objExcel = CreateObject("Excel.Application")
Set objWorkbook = objExcel.Workbooks.Open("D:\Book2.xlsx")
objWorkbook.Save
objWorkbook.Close 
objExcel.Quit
Set objExcel = Nothing
Set objWorkbook = Nothing

and then you can write R code as cell A4 has formula in Book1.xlsx as =A3*5

mywritexlsx(fname="d:/Book1.xlsx",data = 20,startCol = 1,startRow = 3)
system("cp d:\\Book1.xlsx d:\\Book2.xlsx")
system("cscript //nologo d:\\opensaveexcel.vbs")
tdt1=read.xlsx(xlsxFile = "d:/Book1.xlsx",sheet = "Sheet1",colNames = FALSE)
tdt2=read.xlsx(xlsxFile = "d:/Book2.xlsx",sheet = "Sheet1",colNames = FALSE)

Works for me by the way mywritexlsx is as

mywritexlsx<-function(fname="temp.xlsx",sheetname="Sheet1",data,
                  startCol = 1, startRow = 1, colNames = TRUE, rowNames = FALSE)
{
  if(!file.exists(fname))
  {
   wb = openxlsx::createWorkbook()
   sheet = openxlsx::addWorksheet(wb, sheetname)
  }
  else
 {
   wb <- openxlsx::loadWorkbook(file =fname)
   if(!(sum(openxlsx::getSheetNames(fname)==sheetname)))
   sheet = openxlsx::addWorksheet(wb, sheetname)
   else
    sheet=sheetname
  }

  openxlsx::writeData(wb,sheet,data,startCol = startCol, startRow = startRow, 
          colNames = colNames, rowNames = rowNames)
  openxlsx::saveWorkbook(wb, fname,overwrite = TRUE)
}