similar to: RFC: tapply(*, ..., init.value = NA)

On Fri, Jan 27, 2017 at 12:34 AM, Martin Maechler <maechler at stat.math.ethz.ch> wrote: > > > On Jan 26, 2017 07:50, "William Dunlap via R-devel" <r-devel at r-project.org> > > wrote: > > > It would be cool if the default for tapply's init.value could be > > FUN(X[0]), so it would be 0 for FUN=sum or FUN=length, TRUE for >

The "no factor combination" case is distinguishable by 'tapply' with simplify=FALSE. > D2 <- data.frame(n = gl(3,4), L = gl(6,2, labels=LETTERS[1:6]), N=3) > D2 <- D2[-c(1,5), ] > DN <- D2; DN[1,"N"] <- NA > with(DN, tapply(N, list(n,L), FUN=sum, simplify=FALSE)) A B C D E F 1 NA 6 NULL NULL NULL NULL 2 NULL NULL 3 6

> On Jan 26, 2017 07:50, "William Dunlap via R-devel" <r-devel at r-project.org> > wrote: > It would be cool if the default for tapply's init.value could be > FUN(X[0]), so it would be 0 for FUN=sum or FUN=length, TRUE for > FUN=all, -Inf for FUN=max, etc. But that would take time and would > break code for which FUN did not work on

On a related note, the storage mode should try to match ans[[1]] (or unlist:ed and) when allocating 'ansmat' to avoid coercion and hence a full copy. Henrik On Jan 26, 2017 07:50, "William Dunlap via R-devel" <r-devel at r-project.org> wrote: It would be cool if the default for tapply's init.value could be FUN(X[0]), so it would be 0 for FUN=sum or FUN=length, TRUE

Last week, we've talked here about "xtabs(), factors and NAs", -> https://stat.ethz.ch/pipermail/r-devel/2017-January/073621.html In the mean time, I've spent several hours on the issue and also committed changes to R-devel "in two iterations". In the case there is a *Left* hand side part to xtabs() formula, see the help page example using 'esoph', it

It would be cool if the default for tapply's init.value could be FUN(X[0]), so it would be 0 for FUN=sum or FUN=length, TRUE for FUN=all, -Inf for FUN=max, etc. But that would take time and would break code for which FUN did not work on length-0 objects. Bill Dunlap TIBCO Software wdunlap tibco.com On Thu, Jan 26, 2017 at 2:42 AM, Martin Maechler <maechler at stat.math.ethz.ch> wrote:

On 'aggregate data.frame', the URL should be https://stat.ethz.ch/pipermail/r-help/2016-May/438631.html . vector(typeof(ans)) (or vector(storage.mode(ans))) has length zero and can be used to initialize array. Instead of if(missing(default)) , if(identical(default, NA)) could be used. The documentation could then say, for example: "If default = NA (the default), NA of appropriate

Dear R-developers, when tapply() is invoked on factors that have empty levels, it returns NA. This behaviour is in accord with the tapply documentation, and is reasonable in many cases. However, when FUN is sum, it would also seem reasonable to return 0 instead of NA, because "the sum of an empty set is zero, by definition." I'd like to raise a discussion of the possibility of an

Though tapply(x, factor, fun, simplify =TRUE) should be equivalent to sapply(split(x, factor), fun, simplify=TRUE), note simplify=TRUE, it is not so if fun() returns a vector rather than a scalar, e.g. > tapply(1:6, c(0,0,0,1,1,1), function(x) c(min=min(x), max=max(x)), simplify=TRUE) $"0" min max 1 3 $"1" min max 4 6 > sapply(split(1:6, c(0,0,0,1,1,1)),

summary: The function 'by' inconsistently strips class from the data to which it is applied. quick reason: tapply strips class when simplify is set to TRUE (the default) due to the class stripping behaviour of unlist. quick answer: This can be fixed by invoking tapply with simplify=FALSE, or changing tapply to use do.call(c instead of unlist executable example:

The function tapply is not working in the Windows version of R=20 (Version 0.50 Beta (Sept 29, 1997)) In tapply <- function (x, INDEX, FUN=3DNULL, simplify=3DTRUE, ...)=20 ... The part: if (simplify && all(unlist(lapply(ans, length)) =3D=3D 1)) { ans <- unlist(ans, recursive =3D FALSE) names(ans)<-namelist[[1]] return(ans) } should be replaced by if (simplify

Full_Name: Hilmar Berger Version: 2.4.1/2.6.2alpha OS: WinXP Submission from: (NULL) (84.185.128.110) Hi all, If I use tapply on an empty data.frame I get an error. I'm not quite sure if one can actually expect the function to return with a result. However, the error message suggests that this case does not get handled well. This happens both in R-2.4.1 and 2.6.2alpha (version 2008-01-26).

Hello, I found rather surprising the behaviour of POSIXct and POSIXlt classes when combined with min and tapply. The details can be deduced from the script below: ############# Start of the script #################### before <- Sys.time() Sys.sleep( 1 ) now1 <- now2 <- Sys.time() my.times <- c( before, now1, now2 ) class( my.times ) ## [1] "POSIXct"

Hi, all. The help file for tapply says that if simplify is true, and the result of the calculation is always a scalar, then tapply will return a vector. Nonetheless: > t1 <- tapply(runif(10), rep(1:5, 2), mean) > is.vector(t1) [1] FALSE > is.array(t1) [1] TRUE > I have found this in version 0.65.1 on an SGI running Irix 6.5, and on a Mac running Linux-PPC. I've also

Function 'tapply' in R devel r72137 uses if(!is.null(ans) && is.na(default) && is.atomic(ans)) . Problems: - It is possible that user-specified 'default' is not of length 1. If the length is zero, the 'if' gives an error. - It is possible that is.na(default) is TRUE and user-specified 'default' is NaN. --------------------------------------------

I'm trying to find a more elegant way of doing this. What I'm trying to accomplish is to count the frequency of letters (major / minor alleles) in a string grouped by the factor levels in another column of my data frame. Ex. > DF<-data.frame(c("CC", "CC", NA, "CG", "GG", "GC"), c("L", "U", "L",

i use tapply and by often, but i always end up banging my head against the wall with the output. is there a simpler way to convert the output of the following tapply to a dataframe or matrix than what i have here: # setup data for tapply dt = data.frame(bucket=rep(1:4,25),val=rnorm(100)) fn = function(x) { ret = c(unname(quantile(x,probs=seq(.25,.75,.25),na.rm=T)),mean(x,na.rm=T)) } a =

Hi, I'm building a matrix m from a data frame d which includes the matrix row, column and value. This works well enough: m <- tapply(d[,"value"],d[,c("row","column")],c) However, I'd like to replace any missing values with 0, not NA. The obvious doesn't work, however: m <-

Hi all, The documentation for head() and tail() describes the behavior of these generic functions when n is strictly positive (n > 0) and strictly negative (n < 0). How these functions work when given a zero value is not defined. Both GNU command-line utilities head and tail behave differently with +0 and -0: http://man7.org/linux/man-pages/man1/head.1.html

After some fiddling around with the tapply command, I discovered that the factors (the INDEX argument) given to tapply must be specified in fastest-cycling first order. The following code shows how I discovered my error: (R version 1.2.1) -o-o-o-o-o- x <- as.data.frame(list(data=c(-9,0,3,1,-9,1,0,-9,0,3,1,-9,1,0), subj=c(rep(1,7),rep(2,7)),