I was wrong, as I didn't actually try and didn't read the documentation
carefully. I thought that ' zero-length arguments being recycled to "" '
happens when recycle0 = TRUE. It is actually the opposite.
Everywhere in my previous message, recycle0 = FALSE should be recycle0 = TRUE.
I really think that 'paste' with 'collapse' specified (as a character string)
should always result in a single character string, no matter what value of
'recycle0'.
paste(character(0), collapse = "", recycle0 = TRUE) # character(0), but should
be ""
paste(character(0), recycle0 = FALSE)
is the same as
paste(character(0), recycle0 = TRUE) .
'recycle0' doesn't matter there.
Why should
paste(character(0), collapse = "", recycle0 = FALSE)
be different from
paste(character(0), collapse = "", recycle0 = TRUE) ?
paste(c("4", "5"), "th", sep = "", collapse = ", ", recycle0 = TRUE) # "4th,
5th"
paste(c("4" ), "th", sep = "", collapse = ", ", recycle0 = TRUE) # "4th"
paste(c( ), "th", sep = "", collapse = ", ", recycle0 = TRUE) #
character(0), but should be ""
On Saturday, 2 May 2020, 10:09:21 pm GMT+7, Martin Maechler
<maech...@stat.math.ethz.ch> wrote:
>>>>> suharto anggono--- via R-devel
>>>>> on Fri, 1 May 2020 03:05:37 +0000 (UTC) writes:
> Without 'collapse', 'paste' pastes (concatenates) its arguments
elementwise (separated by 'sep', " " by default). New in R devel and R patched,
specifying recycle0 = FALSE makes mixing zero-length and nonzero-length
arguments results in length zero.
That's not intended.
(It's what should only happen with the new (non-default) recycle0=TRUE )
> The result of paste(n, "th", sep = "", recycle0 = FALSE) always have the same
> length as 'n'. Previously, the result is still as long as the longest
> argument, with the zero-length argument like "". If all og the arguments have
> length zero, 'recycle0' doesn't matter.
> As far as I understand, 'paste' with 'collapse' as a character string is
supposed to put together elements of a vector into a single character string. I
think 'recycle0' shouldn't change it.
Well, not quite: only 'recycle0=FALSE' shouldn't change it
.. maybe this is what you meant anyway.
> In current R devel and R patched, paste(character(0), collapse = "",
recycle0 = FALSE) is character(0). I think it should be "", like
paste(character(0), collapse="").
Definitely: The intent of the new 'recycle0' argument is to
provide a non-default possibility for paste(...., recycle0=TRUE) to behave more
like "arithmetic" functions where the recycling rules ensure that
if one argument has length 0 then the result has length 0:
i.e., paste(a,b,c,d, recycle0=TRUE) should recycle the same as
a+b+c+d does recycle
Indeed, the default 'recycle0=FALSE' should correspond to previous (R <= 4.0.0)
behavior entirely.
BUT from all I see, R-devel and R-patched's version of paste()
do behave as they should. Also what you clim here is not true :
> paste(c("4", "5"), "th", sep = "", collapse = ", ", recycle0 = FALSE)
> is
> "4th, 5th".
> paste(c("4" ), "th", sep = "", collapse = ", ", recycle0 = FALSE)
> is
> "4th".
> I think
> paste(c( ), "th", sep = "", collapse = ", ", recycle0 = FALSE)
> should be
> "",
> not character(0).
Rather, what I see is what the comments of the following code
lines claim (according to the intention of 'recycle0', contrary
some of your claims above) :
paste(character(0), collapse = "", recycle0 = FALSE) # is "", like
paste(character(0), collapse = "")
paste(character(0), collapse = "", recycle0 = TRUE) # is character(0)
paste(c("4", "5"), "th", sep = "", collapse = ", ", recycle0 = FALSE) # is
"4th, 5th"
paste(c("4" ), "th", sep = "", collapse = ", ", recycle0 = FALSE) # is "4th"
paste(c( ), "th", sep = "", collapse = ", ", recycle0 = FALSE) # is "th"
##
paste(c("4", "5"), "th", sep = "", collapse = ", ", recycle0 = TRUE) # is
"4th, 5th"
paste(c("4" ), "th", sep = "", collapse = ", ", recycle0 = TRUE) # is "4th"
paste(c( ), "th", sep = "", collapse = ", ", recycle0 = TRUE) # is
character(0)
There must be a lapsus / misunderstanding somewhere.
I don't see any problem in the new behavior for now.
Best regards,
Martin
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