从文本文件中读取特定列：R

Question

我正在尝试读取文本文件并创建一些特定列（大约12个）（以一定长度定位）的数据框（称为数据集），如下所示：

  x <- fread("file1.txt",colClasses = "character", sep = "\n", header = FALSE, verbose = FALSE,strip.white = FALSE)
  y <- fread("file2.txt",colClasses = "character", sep = "\n", header = FALSE, verbose = FALSE,strip.white = FALSE)
  # combine them
  x = rbind(x,y)


  # We basically read the whole file as a string and then read substrings 
  # corresponding to each variable start and finish lengths.
  Var1= sapply(as.list(x$V1), stri_sub, from = 80, to = 82)
  Var1= as.data.frame(Var1)

  Var2= sapply(as.list(x$V1), stri_sub, 83, 89)
  Var2= as.data.frame(Var2)

  dataset = cbind(Var1,Var2)

运行两个分别具有200K和300K行的文本文件大约需要1分钟。每行有1800个字符。有没有更快的方法来运行它？我将阅读大约200个此类文件。

Answer 1