CODEWITHSUNDEEP
r
CroatiaHR
CroatiaHR

Reputation: 625

Appending file name to data frame in R

I want to append the file name to my table, but it seems it is not really working.
What I am doing is iterating over a list of filenames, opening them, appending all the data to one data frame and for each appended file I want to add its file name. I expect it to be appended on each row, so that later when I look at the data, I would know from which file is the given row originating.
But it seems that it is not working as expected.

data <- data.frame()
for (file in files){

  name = strsplit(file, split = "\\.")[[1]][1]

  data <- data %>% bind_rows(read_delim(file = file, delim = ";", col_types = cols(
    a = col_double(),
    b = col_double(),
    )) %>% mutate(name = name))
}

I believed that the mutate function should have done the trick, apparently, in the end they all have the same value.

Upvotes: 2

Views: 1722

Answers (1)

akrun
akrun

Reputation: 886948

As we are using tidyverse, an option is

library(readr)
library(purrr)
files_no_ext <- tools::file_path_sans_ext(files)
out <- imap_dfr(set_names(files, files_no_ext), ~ 
      read_delim(.x, delim = ";", 
         col_types = cols(a = col_double(),b = col_double()),
              .id = 'name')

Or using data.table

library(data.table)
out <- rbindlist(lapply(setNames(files, files_no_ext), fread), idcol = 'name')

In the OP's for loop

dat <- data.frame()
for (file in files){
     name <- tools::file_path_sans_ext(file)
     tmpdat <- read_delim(file = file, delim = ";", 
             col_types = cols(
                    a = col_double(),
                    b = col_double()
                      )) %>%
              mutate(name = name)
      dat <- rbind(dat, tmpdat)

 }

Upvotes: 2

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