R - OpenXLSX - Applying formatting / setting a style to a formula

Question

Via openxlsx I'm populating an Excel-file, with both data and formulas. For some cells formatting is required, for example on percentages, which can be done by either assigning percentage to the class or by applying a style. However, this does not work for formulas. Below is an example with 4 entries: the first two are data and are correctly displayed as percentages. Entries 3 and 4 are formulas, with entry 3 using class to set formatting, while entry 4 uses addStyle

  # Create workbook
  wb <- createWorkbook()
  # Add new orksheet
  addWorksheet(wb, sheetName = "Test")
  x <- 0.05
  class(x) <- c(class(x), "percentage")
  writeData(wb, sheet = "Test", x = x, startRow = 1, startCol = 1, rowNames = FALSE, colNames = FALSE)
  x <- 0.07
  class(x) <- c(class(x), "percentage")
  writeData(wb, sheet = "Test", x = x, startRow = 2, startCol = 1, rowNames = FALSE, colNames = FALSE)
  x <- "A1+A2"
  class(x) <- c(class(x), "percentage")
  writeFormula(wb, sheet = "Test", x = x, startRow = 3, startCol = 1)
  x <- "A1+A2"
  writeFormula(wb, sheet = "Test", x = x, startRow = 4, startCol = 1)
  number_format <- createStyle(numFmt = openxlsx_getOp("numFmt", "PERCENTAGE"))
  addStyle(wb, sheet = sheet, number_format,
           rows = 4:4, cols = 1:1, gridExpand = FALSE)
  
  # Store the Excel-file
  saveWorkbook(wb, "test_model1.xlsx", overwrite = TRUE)

The resulting WB:

This is likely due to the formula being written as character. After pressing enter , the correct formatting does appear. This was also the case at Display as percentages using openxlsx::addStyle without having to click on cell in Excel , but there no solution is provided.

Answer 1

Turns out the problem was in creating the style:

  number_format <- createStyle(numFmt = openxlsx_getOp("numFmt", "PERCENTAGE"))

Should be

  number_format <- createStyle(numFmt = "percentage")

Also in some cases it helped to first apply the style, and then fill in the data/formula.