similar to: A suggestion for an amendment to tapply

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

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 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 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

Function 'aggregate.data.frame' in R has taken a different route. With drop=FALSE, the function is also applied to subset corresponding to combination of grouping variables that doesn't appear in the data (example 2 in https://stat.ethz.ch/pipermail/r-devel/2017-January/073678.html). Because 'default' is used only when simplification happens, putting 'default' after

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

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"

First, here's the problem I'm working on so you understand the context. I have a data frame of travel activity characteristics with 70,000+ records. These activities are identified by unique chain numbers. (Activities are part of trip chains.) There are 17,500 chains. I use the chain numbers as factors to split various data fields into lists of chain characteristics with each element of

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

A few problems in R-0.50-a3 (which were also in R-0.49): 1) y <- c(10,11,12,13,14,NA,NA) n <- length(y) missed <- (1:n)[is.na(y)] notmissed <- (1:n)[!is.na(y)] blocks <- cut(missed,breaks=c(0,notmissed,n+1)) a <- function(v) { q <- range(v) c(q[1]-1,q[2]+1) } brackets <- tapply(missed,blocks,a) This codes gives the following in S: > brackets $"0+ thru 1":

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. --------------------------------------------

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

Is the following behaviour of tapply not disappointing? Problem with tapply occurs when dealing with na.rm when an argument additional to na.rm is sent to the applied function (here quantile). Any comment? Thank you, Philippe Lambert > x <- c(12,10,12,2,4,11,3,7,2,1,18,7,NA,NA,7,5) > fac <- gl(4,4,16) > # Works fine > tapply(x,fac,quantile,na.rm=T) $"1" 0% 25%

Hello r-help, I am trying to collapse or aggregate 'some' of a data frame. A very simplified version of my data frame looks like: > tester trip set num sex lfs1 lfs2 1 313 15 5 M 2 3 2 313 15 3 F 1 2 3 313 17 1 M 0 1 4 313 17 2 F 1 1 5 313 17 1 U 1 0 And I want to omit sex from the picture and just get an addition of num,