R：從多個文件路徑導入數據並存儲在列表中

Question

我有一些數據，我想根據各個路徑從單獨的.txt文件中讀取。 帶有txt文件的示例文件夾結構可以在此處下載。

我擁有的（樣本）data.frame看起來像這樣

data <-   structure(list(Name = structure(c(1L, 3L, 4L, 2L), .Label = c("Test1", "Test10", "Test2", "Test6"), class = "factor"), Metadata = structure(c(3L, 4L, 1L, 2L), .Label = c("asdajl7", "asfhas", "sgash", "uashas8"), class = "factor"), Filepath = structure(c(2L, 3L, 4L, 1L), .Label = c("", "Folder1/File8.txt", "Folder7/file2.txt", "Folder9/File19.txt"), class = "factor")), .Names = c("Name", "Metadata", "Filepath"), class = "data.frame", row.names = c(NA, -4L))

data
    Name Metadata           Filepath
1  Test1    sgash  Folder1/File8.txt
2  Test2  uashas8  Folder7/file2.txt
3  Test6  asdajl7 Folder9/File19.txt
4 Test10   asfhas

為了提供一個可復制的示例，我嘗試實現以下功能以將文件路徑調整為您從上面的下載中保存文件夾結構的位置。

# Choose path to unzipped Data directory
choose.dir <- function() {
  system("osascript -e 'tell app \"R\" to POSIX path of (choose folder with prompt \"Choose Data Folder:\")' > /tmp/R_folder",
         intern = FALSE, ignore.stderr = TRUE)
  p <- system("cat /tmp/R_folder && rm -f /tmp/R_folder", intern = TRUE)
  return(ifelse(length(p), p, NA))
}
a <- choose.dir()
if(is.na(a)) stop("No folder", call. = F)
# paste ready to use path together
data$completepath <- paste0(a,"/",data$Filepath)
data$completepath <- gsub("//", "/", data$completepath)

現在，data.frame如下所示（我將文件夾結構解壓縮到了桌面上）：

data
    Name Metadata           Filepath                               completepath
1  Test1    sgash  Folder1/File8.txt  /Users/XYZ/Desktop/Data/Folder1/File8.txt
2  Test2  uashas8  Folder7/file2.txt  /Users/XYZ/Desktop/Data/Folder7/file2.txt
3  Test6  asdajl7 Folder9/File19.txt /Users/XYZ/Desktop/Data/Folder9/File19.txt
4 Test10   asfhas                                      /Users/XYZ/Desktop/Data/

如何使用循環從不同的.txt文件中讀取數據，以便獲得以下列表結構？

   List with 3 elements
        1.1 (5 observations and 5 Variables)
        $Name chr[1:5] Test1 Test1 Test1 Test1 Test1
        $Year num[1:5] 1783 1784 1785 1786 1787
        $data1 num[1:5] 12 53 13.1 12.9 16
        $data2 num[1:5] 56 5 532 27 9
        $data3 num[1:5] 0.1 9 42 2 13
        1.2 (4 observations and 3 variables)
        $Name chr[1:4] Test2 Test2 Test2 Test2
        $Year num[1:4] 1387 1388 1389 1390
        $data num[1:4] 78.9 27 12.3 0.9
        1.3 (3 observations and 3 variables)
        $Name chr[1:3] Test6 Test6 Test6
        $Test1 chr[1:3] hajshf asfhah ashsa
        $Year num[1:3] 2001 2002 2003

我嘗試了以下操作，但是由於Test10的空文件路徑導致了問題，因此無法正常工作。 有人能幫我嗎？

# read in the data
f <- file.path(data$completepath)
d <- lapply(f, read.table)

Answer 1

您不必這樣做，您可以寫出路徑

setwd("/home/christie/Downloads/Data/")

這將提供工作目錄中每個文件的所有路徑

files<-list.files(getwd(),recursive=TRUE)

這會將它們全部讀入列表

d<-lapply(files,function(x) read.table(x, header=T))

str(d)
List of 3
 $ :'data.frame':   5 obs. of  4 variables:
  ..$ data1: num [1:5] 12 53 13.1 12.9 16
  ..$ data2: int [1:5] 56 5 532 27 9
  ..$ data3: num [1:5] 0.1 9 42 2 13
  ..$ year : int [1:5] 1783 1784 1785 1786 1787
 $ :'data.frame':   4 obs. of  2 variables:
  ..$ data: num [1:4] 78.9 27 12.3 0.9
  ..$ year: int [1:4] 1387 1388 1389 1390
 $ :'data.frame':   3 obs. of  3 variables:
  ..$ data1: int [1:3] 18 39 371
  ..$ Test1: Factor w/ 3 levels "asfhah","ashsa",..: 3 1 2
  ..$ Year : int [1:3] 2001 2002 2003