Quoting "Heuvel, E.G. van den (Guido) via R-help" <r-help@r-project.org>:
Hi all,
I encountered some weird behaviour with readLines() recently, and I
am wondering if this might be a bug, or, if it is not, how to
resolve it. The issue is as follows:
If I have a text file where a line ends with just a carriage return
(\r, CR) while the next line is empty and ends in a carriage return
/ linefeed (\r\n, CR LF), then the empty line is skipped when
reading the file with readLines. The following code contains a test
case:
---
print(R.version)
# platform x86_64-w64-mingw32
# arch x86_64
# os mingw32
# crt ucrt
# system x86_64, mingw32
# status
# major 4
# minor 4.0
# year 2024
# month 04
# day 24
# svn rev 86474
# language R
# version.string R version 4.4.0 (2024-04-24 ucrt)
# nickname Puppy Cup
txt_original <- paste0("Line 1\r", "\r\n", "Line 3\r\n")
# Write txt_original as binary to avoid unwanted conversion of end
of line markers
writeBin(charToRaw(txt_original), "test.txt")
txt_actual <- readLines("test.txt")
print(txt_actual)
# [1] "Line 1" "Line 3"
---
I included the output of this script on my machine in the comments.
I would expect txt_actual to be equal to c("Line 1", "", "Line 3"),
but the empty line is skipped.
Is this a bug? And if not, how should I read test.txt in such a way
that the empty 2nd line is left intact?
Best regards,
Guido van den Heuvel
Statistics Netherlands
What would be your "rule" for identifying lines? From your desired output,
it seems \r should be end-of-line, and \n is to be ignored. Then you could
do something like that:
raw <- readChar("test.txt", 1000)
raw <- gsub("\n", "", raw)
strsplit(raw, "\r")[[1]]
## [1] "Line 1" "" "Line 3"
But it requires you to specify the number of characters to read (or write a
loop).
--
Enrico Schumann
Lucerne, Switzerland
https://enricoschumann.net
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