readline in function call with space in prompt.

Hello,

I have noticed a behavior that I don't understand. When I call the
following function from the prompt.
test <- function(){
    a <- readline("selection: ")
    a
}
test()
selection: |
I can only type one character and the readline function exits before I can
press enter.

however

test1 <- function(){
    a <- readline("selection:")
    a
}
test1()
selection:|
works as expected.
selection: abc[Ret]
However calling directly readline with a space in the prompt does what I
would expect.
a <- readline("selection: ")
selection: abc[Ret]
a
"abc"
It is the expected behavior or am I missing something?

Best regards,
Jeremie
Jeremie Juste
> R version 4.0.3 (2020-10-10)
Hi Jeremie,
Try this:

test <- function() {
 a<-readline("selection: ")
 return(a)
}

If it starts working, it could be a difference in the way Windows R
handles text input. Both work okay for me on fedora linux.

Jim
Hello,

I have noticed a behavior that I don't understand. When I call the
following function from the prompt.
test <- function(){
    a <- readline("selection: ")
    a
}

test()
selection: |
I can only type one character and the readline function exits before I can
press enter.

however

test1 <- function(){
    a <- readline("selection:")
    a
}
test1()
selection:|
works as expected.
selection: abc[Ret]
However calling directly readline with a space in the prompt does what I
would expect.

a <- readline("selection: ")
selection: abc[Ret]
a
"abc"
It is the expected behavior or am I missing something?

Best regards,
Jeremie
--
Jeremie Juste
R version 4.0.3 (2020-10-10)

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On Mon, 08 Feb 2021 14:28:33 +0100

Hello,

I have noticed a behavior that I don't understand. When I call the
following function from the prompt.
test <- function(){
    a <- readline("selection: ")
    a
}

test()
selection: |
I can only type one character and the readline function exits before
I can press enter.

however

test1 <- function(){
    a <- readline("selection:")
    a
}
test1()
selection:|
works as expected.
selection: abc[Ret]
However calling directly readline with a space in the prompt does
what I would expect.

a <- readline("selection: ")
selection: abc[Ret]
a
"abc"
It is the expected behavior or am I missing something?
Works fine for me, with or without the space in the prompt string.
There *must* be something flaky in your system, but I'm damned if I can
come up with any useful suggestions for tracking down just where that
flakiness lies.  Sorry.

Perhaps try re-installing R???

cheers,

Rolf Turner
Honorary Research Fellow
Department of Statistics
University of Auckland
Phone: +64-9-373-7599 ext. 88276
Jeremie Juste 
    on Mon, 08 Feb 2021 14:28:33 +0100 writes:
> Hello,
    > I have noticed a behavior that I don't understand. When I call the
    > following function from the prompt.
    > test <- function(){
    > a <- readline("selection: ")
    > a
    > }

    >> test()
    >> selection: |
    > I can only type one character and the readline function exits before I can
    > press enter.

    > however

    > test1 <- function(){
    > a <- readline("selection:")
    > a
    > }
    >> test1()
    >> selection:|
    > works as expected.
    >> selection: abc[Ret]

    > However calling directly readline with a space in the prompt does what I
    > would expect.

    >> a <- readline("selection: ")
    >> selection: abc[Ret]
    >> a
    >> "abc"

    > It is the expected behavior or am I missing something?

    > Best regards,
    > Jeremie
    > -- 
    > Jeremie Juste
    >> R version 4.0.3 (2020-10-10)

Given that the above works fine in Linux (for Jim Lemon and Rolf Turner),

could you tell us *how* you use R?
In the (Windows) RGui  or from Rstudio  or  ESS   or yet another way?

Usually the UI (user interface) should not matter, but rather
the R version etc.
But the UI may be important for a function like readline()
which does UI ..

Martin
The function test as defined below by Jeremie works as I would have 
expected for me on Windows so I am unable to replicate the problem there.

R version 4.0.3 (2020-10-10)
Platform: x86_64-w64-mingw32/x64 (64-bit)
Running under: Windows 10 x64 (build 19041)

Matrix products: default

locale:
[1] LC_COLLATE=English_United Kingdom.1252
[2] LC_CTYPE=English_United Kingdom.1252
[3] LC_MONETARY=English_United Kingdom.1252
[4] LC_NUMERIC=C
[5] LC_TIME=English_United Kingdom.1252

attached base packages:
[1] stats     graphics  grDevices utils     datasets  methods   base

loaded via a namespace (and not attached):
[1] compiler_4.0.3
Jeremie Juste
     on Mon, 08 Feb 2021 14:28:33 +0100 writes:

     > Hello,
     > I have noticed a behavior that I don't understand. When I call the
     > following function from the prompt.
     > test <- function(){
     > a <- readline("selection: ")
     > a
     > }

     >> test()
     >> selection: |
     > I can only type one character and the readline function exits before I can
     > press enter.

     > however

     > test1 <- function(){
     > a <- readline("selection:")
     > a
     > }
     >> test1()
     >> selection:|
     > works as expected.
     >> selection: abc[Ret]

     > However calling directly readline with a space in the prompt does what I
     > would expect.

     >> a <- readline("selection: ")
     >> selection: abc[Ret]
     >> a
     >> "abc"

     > It is the expected behavior or am I missing something?

     > Best regards,
     > Jeremie
     > --
     > Jeremie Juste
     >> R version 4.0.3 (2020-10-10)
Given that the above works fine in Linux (for Jim Lemon and Rolf Turner),

could you tell us *how* you use R?
In the (Windows) RGui  or from Rstudio  or  ESS   or yet another way?

Usually the UI (user interface) should not matter, but rather
the R version etc.
But the UI may be important for a function like readline()
which does UI ..

Martin

______________________________________________
R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.

Michael
http://www.dewey.myzen.co.uk/home.html