R devel - May 2020 - paste(character(0), collapse="", recycle0=FALSE) should be ""

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. 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.

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="").

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).

>>>>> 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

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 <maechler at
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  
	[[alternative HTML version deleted]]

I agree: paste(collapse="something", ...) should always return a
single
character string, regardless of the value of recycle0.  This would be
similar to when there are no non-NULL arguments to paste; collapse="."
gives a single empty string and collapse=NULL gives a zero long character
vector.
> paste()
character(0)
> paste(collapse=", ")
[1] ""

Bill Dunlap
TIBCO Software
wdunlap tibco.com


On Thu, Apr 30, 2020 at 9:56 PM suharto_anggono--- via R-devel <
r-devel at r-project.org> wrote:
> 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. 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.
>
> 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="").
>
> 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).
>
> ______________________________________________
> R-devel at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-devel
>
	[[alternative HTML version deleted]]

Totally agree with that.

H.

On 5/15/20 10:34, William Dunlap via R-devel wrote:
> I agree: paste(collapse="something", ...) should always return a
single
> character string, regardless of the value of recycle0.  This would be
> similar to when there are no non-NULL arguments to paste;
collapse="."
> gives a single empty string and collapse=NULL gives a zero long character
> vector.
>> paste()
> character(0)
>> paste(collapse=", ")
> [1] ""
> 
> Bill Dunlap
> TIBCO Software
> wdunlap tibco.com
> 
> 
> On Thu, Apr 30, 2020 at 9:56 PM suharto_anggono--- via R-devel <
> r-devel at r-project.org> wrote:
> 
>> 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. 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.
>>
>> 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="").
>>
>> 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).
>>
>> ______________________________________________
>> R-devel at r-project.org mailing list
>>
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> 
> 	[[alternative HTML version deleted]]
> 
> ______________________________________________
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-- 
Herv? Pag?s

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