Add “filename” column to table as multiple files are read and bound

Question

I have numerous csv files in multiple directories that I want to read into a R tribble or data.table. I use \"list.files()\" with the recursive argument set to TRUE to creat

Answer 1

You can build a filenames vector based on "sites" with the exact same length as tbl and then combine the two using cbind

### Get file names
filenames <- list.files(path, full.names = TRUE, pattern = fileptrn, recursive = TRUE)
sites <- str_extract(filenames, "[A-Z]{2}-[A-Za-z0-9]{3}")

### Get length of each csv
file_lengths <- unlist(lapply(lapply(filenames, read_csv), nrow))

### Repeat sites using lengths
file_names <- rep(sites,file_lengths))

### Create table
tbl <- lapply(filenames, read_csv) %>% 
  bind_rows()

### Combine file_names and tbl
tbl <- cbind(tbl, filename = file_names)