遇到错误时从列表中删除文件名

Question

I have this code

library(plyr)
library(readxl)
library(XLConnect)

#Set the Path
layout_path <- "/rdrive/my_test/"
output_path <- "/rdrive/my_test/"

filenames <- list.files(path = layout_path , pattern="*xls", ignore.case=TRUE)
filecount <- length(list.files(path = layout_path, pattern="*xls", ignore.case=TRUE))

err_fs =
  for (f in filenames) {
    tryCatch(
      {
      nverr <- read_excel(paste(layout_path,f,sep=''), sheet = 1, col_names = FALSE, range = cell_cols("A:A"))
      },
      error=function(err) {
        filenames[names(filenames) != f]    
        cat("File doesn't appear to open:", f, conditionMessage(err), "\n")
      })
  }

While everything else seem to be working, filenames[names(filenames) != f] is unable to remove the errored file name from the list 'filenames'. I even tried the number method but all in vein .. could it be because it's inside the error function ?

Appreciate if you can suggest a way out please.

Answer 1

You could create a vector to store the result and turn it to "success" if the file correctly reads and will remain blank in case of error.

file_read <- character(length(filenames))

for (i in seq_along(filenames)) {
  tryCatch(
    {
      nverr <- read_excel(paste(layout_path,filenames[i],sep=''), sheet = 1, col_names = FALSE, range = cell_cols("A:A"))
      file_read[i] <- 'success'
    },
    error=function(err) {
      cat("File doesn't appear to open:", f, conditionMessage(err), "\n")
    })
}

You can then remove the unsuccessful files.

newfilenames <- filenames[file_read != 'success']