[R] Incremental ReadLines

Freds frederiklang at gmail.com
Wed Apr 13 19:57:58 CEST 2011

Hi there,

I am having a similar problem with reading in a large text file with around
550.000 observations with each 10 to 100 lines of description. I am trying
to parse it in R but I have troubles with the size of the file. It seems
like it is slowing down dramatically at some point. I would be happy for any
suggestions. Here is my code, which works fine when I am doing a subsample
of my dataset.

#Defining datasource
file <- "filename.txt"

#Creating placeholder for data and assigning column names
data <- data.frame(Id=NA)

#Starting by case = 0
case <- 0

#Opening a connection to data
input <- file(file, "rt")

#Going through cases
repeat {
  line <- readLines(input, n=1)
  if (length(line)==0) break
  if (length(grep("Id:",line)) != 0) {
    case <- case + 1 ; data[case,] <-NA
    split_line <- strsplit(line,"Id:")
    data[case,1] <- as.numeric(split_line[[1]][2])

#Closing connection

#Saving dataframe

Kind regards,


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