Load multiple txt files to a single data frame and retain name as a column in R

Question

I\'m new to R and I\'m trying to load 100 or so txt files with three columns Name, Frequency and Gender into a single data frame. The files are all name \"yob1990.txt\" etc.

Answer 1

You could also use fread and rbindlist from data.table. If the files are in the working directory,

  f1 <- list.files(pattern="^yob.*\\.txt")
  f1  #created 3 files
  #[1] "yob1990.txt" "yob1991.txt" "yob1992.txt"

  library(data.table)
  library(stringr)
  year <- as.numeric(str_extract(f1, perl("[0-9]+(?=\\.txt)")))
  res <- rbindlist(Map(`cbind`, lapply(f1, fread), year=year))

  head(res)
 #    Name Frequency Gender year
 #1:   Sam        24   Male 1990
 #2:  Gobi        22   Male 1990
 #3:  Rose        44 Female 1990
 #4: Anita        35 Female 1990
 #5:  John        44   Male 1991
 #6: Sofia        52 Female 1991

Or you could use unnest from tidyr

  devtools::install_github("hadley/tidyr")
  library(tidyr)
  res1 <- unnest(setNames(lapply(f1, fread), year), year)
  head(res1)
  #  year  Name Frequency Gender
  #1 1990   Sam        24   Male
  #2 1990  Gobi        22   Male
  #3 1990  Rose        44 Female
  #4 1990 Anita        35 Female
  #5 1991  John        44   Male
  #6 1991 Sofia        52 Female