Re: [Rd] round() ignores missing arguments if it is used inside another function where some arguments are missing.
On Nov 19, 2011, at 04:35 , Henrik Bengtsson wrote: > On Fri, Nov 18, 2011 at 9:34 AM, Kevin R. Coombes > wrote: >> You can also see the odd behavior without wrapping round in another >> function: >> >>> round(100.1, digits=) >> [1] 100 > > Hmm... is there a reason for why the parser accepts that construct? Yes. See e.g. help(alist) for actual usage. It can also be used to pass empty arguments to FUN in apply-constructs: a <- matrix(1:12, 3, 4) f <- function(i, j) a[i,j] lapply(1:4, f, i=) > Some example: > >> parse(text="f(a=)") > expression(f(a=)) > >> parse(text="f[a=]") > expression(f[a=]) > >> parse(text="(a=)") > Error in parse.default(text = "(a=)") : :1:4: unexpected ')' > 1: (a=) > > /Henrik > >> >> On 11/18/2011 10:19 AM, Joris Meys wrote: >>> >>> On Fri, Nov 18, 2011 at 5:10 PM, Gavin Simpson >>> wrote: round is indicated to not evaluate its arguments. I don't follow the C code well enough to know if it should be catching the missing argument further on - it must be because it is falling back to the default, but the above explains that the not evaluating arguments is intended. G >>> >>> So if I understand it right, the y argument is not evaluated in the >>> fun2 function but deeper in the C code. that explains the lack of the >>> error message, thanks! I keep on learning every day. >>> Cheers >>> >>> Joris >>> >> >> __ >> R-devel@r-project.org mailing list >> https://stat.ethz.ch/mailman/listinfo/r-devel >> > > __ > R-devel@r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-devel -- Peter Dalgaard, Professor, Center for Statistics, Copenhagen Business School Solbjerg Plads 3, 2000 Frederiksberg, Denmark Phone: (+45)38153501 Email: pd@cbs.dk Priv: pda...@gmail.com __ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
Re: [Rd] round() ignores missing arguments if it is used inside another function where some arguments are missing.
On Fri, Nov 18, 2011 at 9:34 AM, Kevin R. Coombes wrote: > You can also see the odd behavior without wrapping round in another > function: > >> round(100.1, digits=) > [1] 100 Hmm... is there a reason for why the parser accepts that construct? Some example: > parse(text="f(a=)") expression(f(a=)) > parse(text="f[a=]") expression(f[a=]) > parse(text="(a=)") Error in parse.default(text = "(a=)") : :1:4: unexpected ')' 1: (a=) /Henrik > > On 11/18/2011 10:19 AM, Joris Meys wrote: >> >> On Fri, Nov 18, 2011 at 5:10 PM, Gavin Simpson >> wrote: >>> >>> round is indicated to not evaluate its arguments. I don't follow the C >>> code well enough to know if it should be catching the missing argument >>> further on - it must be because it is falling back to the default, but >>> the above explains that the not evaluating arguments is intended. >>> >>> G >> >> So if I understand it right, the y argument is not evaluated in the >> fun2 function but deeper in the C code. that explains the lack of the >> error message, thanks! I keep on learning every day. >> Cheers >> >> Joris >> > > __ > R-devel@r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-devel > __ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
Re: [Rd] round() ignores missing arguments if it is used inside another function where some arguments are missing.
You can also see the odd behavior without wrapping round in another function: > round(100.1, digits=) [1] 100 On 11/18/2011 10:19 AM, Joris Meys wrote: On Fri, Nov 18, 2011 at 5:10 PM, Gavin Simpson wrote: round is indicated to not evaluate its arguments. I don't follow the C code well enough to know if it should be catching the missing argument further on - it must be because it is falling back to the default, but the above explains that the not evaluating arguments is intended. G So if I understand it right, the y argument is not evaluated in the fun2 function but deeper in the C code. that explains the lack of the error message, thanks! I keep on learning every day. Cheers Joris __ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
Re: [Rd] round() ignores missing arguments if it is used inside another function where some arguments are missing.
On Fri, Nov 18, 2011 at 5:10 PM, Gavin Simpson wrote: > > round is indicated to not evaluate its arguments. I don't follow the C > code well enough to know if it should be catching the missing argument > further on - it must be because it is falling back to the default, but > the above explains that the not evaluating arguments is intended. > > G So if I understand it right, the y argument is not evaluated in the fun2 function but deeper in the C code. that explains the lack of the error message, thanks! I keep on learning every day. Cheers Joris -- Joris Meys Statistical consultant Ghent University Faculty of Bioscience Engineering Department of Mathematical Modelling, Statistics and Bio-Informatics tel : +32 9 264 59 87 joris.m...@ugent.be --- Disclaimer : http://helpdesk.ugent.be/e-maildisclaimer.php __ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
Re: [Rd] round() ignores missing arguments if it is used inside another function where some arguments are missing.
On Fri, 2011-11-18 at 16:43 +0100, Joris Meys wrote:
> I have stumbled across some behaviour in R that I really can't place,
> and that makes coding a bit tricky. I know that I can work around it
> when explicitly checking for missing arguments, but still...
> I have two functions. I have a first function based on paste
>
> fun1 <- function(x,y){
> print(missing(y))
> paste(x,'X',sep=y)
> }
>
> If I try this function without specifying `y`, I get the (expected)
> error message:
>
> > fun1(letters[1:6])
> [1] TRUE
> Error in paste(x, "X", sep = y) :
> argument "y" is missing, with no default
>
> The second one with round :
> fun2 <- function(x,y){ print(missing(y)) round(x,digits=y)}
> If I try this function without specifying `y`, it works unexpectedly
> whereas it shouldn't :
> > fun2(100.1)[1] TRUE[1] 100
round() is implemented as:
> round
function (x, digits = 0) .Primitive("round")
using the .Primitive means of calling C code. `?.Primitve` refers you to
the R Internals manual, which basically states that how the compiled
functions should be called and number of arguments etc is stored in a
table. This table is given here:
http://svn.r-project.org/R/trunk/src/main/names.c
The relevant part of which is:
/* printnamec-entry offset evalarity pp-kind precedence
rightassoc
* ---- -- - --- --
--*/
/* Mathematical Functions */
/* primitives: these are group generic and so need to eval args (possibly
internally) */
{"round", do_Math2, 10001, 0, -1, {PP_FUNCALL, PREC_FN,
0}},
the eval column indicates features of how arguments are evaluated and
what have you. A value of 0 equates to 000 and the last 0 indicates
whether arguments are to be evaluated with 0 indicating no evaluation
and 1 evaluation.
round is indicated to not evaluate its arguments. I don't follow the C
code well enough to know if it should be catching the missing argument
further on - it must be because it is falling back to the default, but
the above explains that the not evaluating arguments is intended.
G
> In my view, fun1 should definitely give the error message as well, as
> it is not intended to have a default behaviour when y is missing.
> Still, the round() function ignores the fact y is missing. Is this by
> design, is there a check missing in round, or is something else going
> on that I am overlooking?
>
> Cheers
> Joris
> > sessionInfo()
> R version 2.14.0 (2011-10-31)
> Platform: i386-pc-mingw32/i386 (32-bit)
>
> 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
> [7] base
>
> loaded via a namespace (and not attached):
> [1] tools_2.14.0
>
--
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Dr. Gavin Simpson [t] +44 (0)20 7679 0522
ECRC, UCL Geography, [f] +44 (0)20 7679 0565
Pearson Building, [e] gavin.simpsonATNOSPAMucl.ac.uk
Gower Street, London [w] http://www.ucl.ac.uk/~ucfagls/
UK. WC1E 6BT. [w] http://www.freshwaters.org.uk
%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%
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Re: [Rd] round() ignores missing arguments if it is used inside another function where some arguments are missing.
On Nov 18, 2011, at 10:43 AM, Joris Meys wrote:
> I have stumbled across some behaviour in R that I really can't place,
> and that makes coding a bit tricky. I know that I can work around it
> when explicitly checking for missing arguments, but still...
> I have two functions. I have a first function based on paste
>
> fun1 <- function(x,y){
> print(missing(y))
> paste(x,'X',sep=y)
> }
>
> If I try this function without specifying `y`, I get the (expected)
> error message:
>
> > fun1(letters[1:6])
> [1] TRUE
> Error in paste(x, "X", sep = y) :
> argument "y" is missing, with no default
>
> The second one with round :
> fun2 <- function(x,y){ print(missing(y)) round(x,digits=y)}
> If I try this function without specifying `y`, it works unexpectedly
> whereas it shouldn't :
> > fun2(100.1)[1] TRUE[1] 100
> In my view, fun1 should definitely give the error message as well, as
> it is not intended to have a default behaviour when y is missing.
> Still, the round() function ignores the fact y is missing. Is this by
> design, is there a check missing in round, or is something else going
> on that I am overlooking?
>
> round
function (x, digits = 0) .Primitive("round")
it has a default so it is fine for digits to be missing since it will have
value 0 in that case ...
Cheers,
S
> Cheers
> Joris
>> sessionInfo()
> R version 2.14.0 (2011-10-31)
> Platform: i386-pc-mingw32/i386 (32-bit)
>
> 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
> [7] base
>
> loaded via a namespace (and not attached):
> [1] tools_2.14.0
>
> --
> Joris Meys
> Statistical consultant
>
> Ghent University
> Faculty of Bioscience Engineering
> Department of Mathematical Modelling, Statistics and Bio-Informatics
>
> tel : +32 9 264 59 87
> joris.m...@ugent.be
> ---
> Disclaimer : http://helpdesk.ugent.be/e-maildisclaimer.php
>
> __
> R-devel@r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-devel
>
>
__
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https://stat.ethz.ch/mailman/listinfo/r-devel
[Rd] round() ignores missing arguments if it is used inside another function where some arguments are missing.
I have stumbled across some behaviour in R that I really can't place,
and that makes coding a bit tricky. I know that I can work around it
when explicitly checking for missing arguments, but still...
I have two functions. I have a first function based on paste
fun1 <- function(x,y){
print(missing(y))
paste(x,'X',sep=y)
}
If I try this function without specifying `y`, I get the (expected)
error message:
> fun1(letters[1:6])
[1] TRUE
Error in paste(x, "X", sep = y) :
argument "y" is missing, with no default
The second one with round :
fun2 <- function(x,y){ print(missing(y)) round(x,digits=y) }
If I try this function without specifying `y`, it works unexpectedly
whereas it shouldn't :
> fun2(100.1) [1] TRUE [1] 100
In my view, fun1 should definitely give the error message as well, as
it is not intended to have a default behaviour when y is missing.
Still, the round() function ignores the fact y is missing. Is this by
design, is there a check missing in round, or is something else going
on that I am overlooking?
Cheers
Joris
> sessionInfo()
R version 2.14.0 (2011-10-31)
Platform: i386-pc-mingw32/i386 (32-bit)
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
[7] base
loaded via a namespace (and not attached):
[1] tools_2.14.0
--
Joris Meys
Statistical consultant
Ghent University
Faculty of Bioscience Engineering
Department of Mathematical Modelling, Statistics and Bio-Informatics
tel : +32 9 264 59 87
joris.m...@ugent.be
---
Disclaimer : http://helpdesk.ugent.be/e-maildisclaimer.php
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