[R] readLines() and unz() and non-empty final line

[Iris Simmons]

Hi Mikko,


I tried running a few different things, and it seems as though
explicitly using `open()` and opening a blocking connection works.

```R
cat("hello", file = "hello.txt")
zip("hello.zip", "hello.txt")
local({
    conn <- unz("hello.zip", "hello.txt")
    on.exit(close(conn))
    ## you can use "r" instead of "rt"
    ##
    ## 'blocking = TRUE' is the default, so remove if desired
    open(conn, "rb", blocking = TRUE)
    readLines(conn)
})
```

A blocking connection might be undesirable for you, in which case
someone else might have a better solution.

On Thu, Oct 24, 2024 at 10:58 AM Marttila Mikko via R-help
<r-help using r-project.org> wrote:
>
> Dear list,
>
> I'm seeing a strange interaction with readLines() and unz() when reading
> a file without an empty final line. The final line gets dropped silently:
>
> > cat("hello", file = "hello.txt")
> > zip("hello.zip", "hello.txt")
>   adding: hello.txt (stored 0%)
> > readLines(unz("hello.zip", "hello.txt"))
> character(0)
>
> The documentation for readLines() says if the final line is incomplete for
> "non-blocking text-mode connections" the line is "pushed back, silently"
> but otherwise "accepted with a warning".
>
> My understanding is that the unz() here is blocking so the line should be
> accepted. Is that incorrect? If so, how would I go about reading such
> lines from a zip file?
>
> Best,
>
> Mikko
>
>
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