Dear All,
where can I find information about how to write an assigment form of a
function?
For curiosity I tried to write a different form of the levels()-function,
since the original method for factor deletes all other attributes of a factor.
Of course, the simple method would be to use instead of levels(x) <-
newlevels, attr(x, 'levels') <- newlevels.
I tried the following:
## example
x <- factor(c(1,1,NA,2,3,4,4,4,1,2)); y <- x
attr(x, 'levels') <- c('a', 'b', 'c',
'd') # does what I want
x
[1] a a <NA> b c d d d a b
Levels: a b c d
'levels.simple<-' <- function (x, value)
{
attr(x, 'levels') <- value
}
levels.simple(y) <- c('a', 'b', 'c', 'd')
# does not what I want
y
[1] "a" "b" "c" "d"
Thanks,
Heinz T??chler
take a look at e.g., get("levels<-.factor"); you should return
"x" in
your function, i.e.,
y <- x <- factor(c(1,1,NA,2,3,4,4,4,1,2))
############
'levels.simple<-' <- function(x, value){
attr(x, 'levels') <- value
x
}
levels.simple(y) <- c('a', 'b', 'c', 'd')
y
I hope it helps.
Best,
Dimitris
----
Dimitris Rizopoulos
Ph.D. Student
Biostatistical Centre
School of Public Health
Catholic University of Leuven
Address: Kapucijnenvoer 35, Leuven, Belgium
Tel: +32/16/336899
Fax: +32/16/337015
Web: http://www.med.kuleuven.be/biostat/
http://www.student.kuleuven.be/~m0390867/dimitris.htm
----- Original Message -----
From: "Heinz Tuechler" <tuechler at gmx.at>
To: <r-help at stat.math.ethz.ch>
Sent: Wednesday, August 10, 2005 2:24 PM
Subject: [R] how to write assignment form of function
Dear All,
where can I find information about how to write an assigment form of a
function?
For curiosity I tried to write a different form of the
levels()-function,
since the original method for factor deletes all other attributes of a
factor.
Of course, the simple method would be to use instead of levels(x) <-
newlevels, attr(x, 'levels') <- newlevels.
I tried the following:
## example
x <- factor(c(1,1,NA,2,3,4,4,4,1,2)); y <- x
attr(x, 'levels') <- c('a', 'b', 'c',
'd') # does what I want
x
[1] a a <NA> b c d d d a b
Levels: a b c d
'levels.simple<-' <- function (x, value)
{
attr(x, 'levels') <- value
}
levels.simple(y) <- c('a', 'b', 'c', 'd')
# does not what I want
y
[1] "a" "b" "c" "d"
Thanks,
Heinz T??chler
______________________________________________
R-help at stat.math.ethz.ch mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide!
http://www.R-project.org/posting-guide.html
At 14:49 10.08.2005 +0200, Dimitris Rizopoulos wrote:>take a look at e.g., get("levels<-.factor"); you should return "x" in >your function, i.e., > >y <- x <- factor(c(1,1,NA,2,3,4,4,4,1,2)) >############ >'levels.simple<-' <- function(x, value){ > attr(x, 'levels') <- value > x > } > >levels.simple(y) <- c('a', 'b', 'c', 'd') >y > > >I hope it helps. > >Best, >Dimitris >Dear Dimitris, Thank you a lot - it helped. Now it works. Heinz>---- >Dimitris Rizopoulos >Ph.D. Student >Biostatistical Centre >School of Public Health >Catholic University of Leuven > >Address: Kapucijnenvoer 35, Leuven, Belgium >Tel: +32/16/336899 >Fax: +32/16/337015 >Web: http://www.med.kuleuven.be/biostat/ > http://www.student.kuleuven.be/~m0390867/dimitris.htm > > >----- Original Message ----- >From: "Heinz Tuechler" <tuechler at gmx.at> >To: <r-help at stat.math.ethz.ch> >Sent: Wednesday, August 10, 2005 2:24 PM >Subject: [R] how to write assignment form of function > > >Dear All, > >where can I find information about how to write an assigment form of a >function? >For curiosity I tried to write a different form of the >levels()-function, >since the original method for factor deletes all other attributes of a >factor. >Of course, the simple method would be to use instead of levels(x) <- >newlevels, attr(x, 'levels') <- newlevels. > >I tried the following: >## example >x <- factor(c(1,1,NA,2,3,4,4,4,1,2)); y <- x >attr(x, 'levels') <- c('a', 'b', 'c', 'd') # does what I want >x > [1] a a <NA> b c d d d a b >Levels: a b c d > >'levels.simple<-' <- function (x, value) > { > attr(x, 'levels') <- value > } > >levels.simple(y) <- c('a', 'b', 'c', 'd') # does not what I want >y >[1] "a" "b" "c" "d" > >Thanks, >Heinz T??chler > >______________________________________________ >R-help at stat.math.ethz.ch mailing list >https://stat.ethz.ch/mailman/listinfo/r-help >PLEASE do read the posting guide! >http://www.R-project.org/posting-guide.html > >
On Wed, 10 Aug 2005, Heinz Tuechler wrote:> where can I find information about how to write an assigment form of a > function?In all good books on S programming, or by studying examples. But in this case the problem is actually about defining functions with the return value you expect.> For curiosity I tried to write a different form of the levels()-function, > since the original method for factor deletes all other attributes of a factor. > Of course, the simple method would be to use instead of levels(x) <- > newlevels, attr(x, 'levels') <- newlevels.And that would not do what the current function does, which is to merge levels as required. I suggest you look at levels<-.factor in R-devel, which does not drop attributes.> I tried the following: > ## example > x <- factor(c(1,1,NA,2,3,4,4,4,1,2)); y <- x > attr(x, 'levels') <- c('a', 'b', 'c', 'd') # does what I want > x > [1] a a <NA> b c d d d a b > Levels: a b c d > > 'levels.simple<-' <- function (x, value) > { > attr(x, 'levels') <- value > }This did not return anything! Try returning 'x'.> levels.simple(y) <- c('a', 'b', 'c', 'd') # does not what I want > y > [1] "a" "b" "c" "d"-- Brian D. Ripley, ripley at stats.ox.ac.uk Professor of Applied Statistics, http://www.stats.ox.ac.uk/~ripley/ University of Oxford, Tel: +44 1865 272861 (self) 1 South Parks Road, +44 1865 272866 (PA) Oxford OX1 3TG, UK Fax: +44 1865 272595
Dear Professor Ripley, thank you for your answer. Adding a return value, as also Dimitris Rizopoulos suggested the function does what I need, that is to rename factor levels. I tried to look at levels<-.factor in R-devel but I have to admit that I do not know exactly where to look and searching I did not find it. For the moment my problem is solved and I interpret your hint that way that in the future levels<-.factor will not more drop all other attributes. Thanks again Heinz T??chler At 15:18 10.08.2005 +0100, Prof Brian Ripley wrote:>On Wed, 10 Aug 2005, Heinz Tuechler wrote: > >> where can I find information about how to write an assigment form of a >> function? > >In all good books on S programming, or by studying examples. But in this >case the problem is actually about defining functions with the return >value you expect. > >> For curiosity I tried to write a different form of the levels()-function, >> since the original method for factor deletes all other attributes of afactor.>> Of course, the simple method would be to use instead of levels(x) <- >> newlevels, attr(x, 'levels') <- newlevels. > >And that would not do what the current function does, which is to merge >levels as required. > >I suggest you look at levels<-.factor in R-devel, which does not drop >attributes. > > >> I tried the following: >> ## example >> x <- factor(c(1,1,NA,2,3,4,4,4,1,2)); y <- x >> attr(x, 'levels') <- c('a', 'b', 'c', 'd') # does what I want >> x >> [1] a a <NA> b c d d d a b >> Levels: a b c d >> >> 'levels.simple<-' <- function (x, value) >> { >> attr(x, 'levels') <- value >> } > >This did not return anything! Try returning 'x'. > >> levels.simple(y) <- c('a', 'b', 'c', 'd') # does not what I want >> y >> [1] "a" "b" "c" "d" > > >-- >Brian D. Ripley, ripley at stats.ox.ac.uk >Professor of Applied Statistics, http://www.stats.ox.ac.uk/~ripley/ >University of Oxford, Tel: +44 1865 272861 (self) >1 South Parks Road, +44 1865 272866 (PA) >Oxford OX1 3TG, UK Fax: +44 1865 272595 > >
At 17:44 10.08.2005 +0100, Patrick Burns wrote:>S Poetry may be of use to you in this.Thank you for the hint and thank you for S Poetry. I like it, I read it, maybe about a year ago, but I don't remember all of it and with all the material I collected about R it's not always easy to remember where I read what. Heinz T??chler> > >Patrick Burns >patrick at burns-stat.com >+44 (0)20 8525 0696 >http://www.burns-stat.com >(home of S Poetry and "A Guide for the Unwilling S User") > >Heinz Tuechler wrote: > >>Dear All, >> >>where can I find information about how to write an assigment form of a >>function? >>For curiosity I tried to write a different form of the levels()-function, >>since the original method for factor deletes all other attributes of afactor.>>Of course, the simple method would be to use instead of levels(x) <- >>newlevels, attr(x, 'levels') <- newlevels. >> >>I tried the following: >>## example >>x <- factor(c(1,1,NA,2,3,4,4,4,1,2)); y <- x >>attr(x, 'levels') <- c('a', 'b', 'c', 'd') # does what I want >>x >> [1] a a <NA> b c d d d a b >>Levels: a b c d >> >>'levels.simple<-' <- function (x, value) >> { >> attr(x, 'levels') <- value >> } >> >>levels.simple(y) <- c('a', 'b', 'c', 'd') # does not what I want >>y >>[1] "a" "b" "c" "d" >> >>Thanks, >>Heinz T??chler >> >>______________________________________________ >>R-help at stat.math.ethz.ch mailing list >>https://stat.ethz.ch/mailman/listinfo/r-help >>PLEASE do read the posting guide!http://www.R-project.org/posting-guide.html>> >> >> >> >> > >