读取同一目录中的所有 Excel 工作簿，每个工作簿都有多个工作表，并将每个工作表导出为 R 中的 a.csv

Question

I am trying to read all sheets from multiple workbooks and then export each sheet as its own.csv. I ran this code:

files.to.read <- list.files(path = "/Users/filelocation", pattern="xlsx",
                            full.names = TRUE)

I then applied this line of code to turn all xlsx in directory to csv, however it doesn't account for the individual sheets within each xlsx file.

lapply(files.to.read, function(x) {
  df = read_excel(x, sheet=1)
  write.csv(df, gsub("xlsx", "csv", x), row.names=FALSE)
})

What's the best way to account for the sheets as well? I tried using excel_sheets() and map_df() in the function but it keeps returning

Error: `path` must be a string

Please help and thank you commmunity!

Answer 1

You need to first read all the workbooks then from each workbook read all the sheets in it.

Using lapply you can try:

library(readxl)

files.to.read <- list.files(path = "/Users/filelocation", 
                            pattern="xlsx", full.names = TRUE)

lapply(files.to.read, function(x) {
  sheets <- excel_sheets(x)
  lapply(sheets, function(y) {
    df = read_excel(x, sheet=y)
    write.csv(df, paste0(tools::file_path_sans_ext(basename(x)), y, '.csv'), 
              row.names=FALSE)  
  })
})

Answer 2

It hard to say which cause the errors without knowing the underline data and what cause the errors so I would modify your code which ensure that it read each sheet and when an error happened it output that error. Please try it and see what is the cause of the error:

library(readxl)

files.to.read <- list.files(path = "/Users/filelocation", pattern="xlsx",
  full.names = TRUE)

read_excel_to_csv <- function(x) {
  sheets <- excel_sheets(x)
  lapply(sheets, function(y) {
    tryCatch({
      df = read_excel(x, sheet=y)
      write.csv(df,
        path = paste0(tools::file_path_sans_ext(basename(x)), "_", y, '.csv'),
        row.names=FALSE)  
    }, error = function(e) {
      print(paste0("Error at file: ", x, " --- sheet: ", y))
    })    
  })
}

lapply(files.to.read, read_excel_to_csv)

@Modify to use part of code for @Ronak's answer