Às 15:43 de 25/06/2025, Enrico Schumann escreveu:
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).
Hello,
Related, output is a mess:
readChar("test.txt", n = file.size("test.txt")) |>
textConnection() |>
readLines()
#> [1] "Line 1" "" "" "Line 3" ""
Is this specific to Windows and to the way it treats "\r"? When I open
the file in Notepad I only see two text lines, but when I open it with
vim, it's
Line 1^M
Line 3
the carriage return is there.
(And when I paste it here
Line 1
Line 3
the <Ctrl+M> becomes an empty line.)
Hope this helps,
Rui Barradas
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