将多个txt文件加载到单个数据帧，并将名称保留为R中的列 [英] Load multiple txt files to a single data frame and retain name as a column in R

问题描述

我是R的新手，我正在尝试加载100个左右的名称，频率和性别的txt文件到一个单一的数据框架。这些文件都是名字yob1990.txt等。

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.

我可以把所有的文件都存入R中，但我不知道如何添加一年的列你可以帮你吗？

I can get all the files into R but I've no idea how to add a column with just the year in it.. can anyone help please?

推荐答案

你也可以使用 fread 和 rbindlist 从 data.table 。如果文件在工作目录中，

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

或者你可以使用 notest 从 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

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