Hi Milu, byapply(df, 12, function(x) apply(x, 1, max))
You might also be interested in the matrixStats package. Best, Ista On Tue, Feb 20, 2018 at 9:55 AM, Miluji Sb <miluj...@gmail.com> wrote: > Dear all, > > I have monthly data in wide format, I am only providing data (at the bottom > of the email) for the first 24 columns but I have 2880 columns in total. > > I would like to take max of every 12 columns. I have taken the mean of > every 12 columns with the following code: > > byapply <- function(x, by, fun, ...) > { > # Create index list > if (length(by) == 1) > { > nc <- ncol(x) > split.index <- rep(1:ceiling(nc / by), each = by, length.out = nc) > } else # 'by' is a vector of groups > { > nc <- length(by) > split.index <- by > } > index.list <- split(seq(from = 1, to = nc), split.index) > > # Pass index list to fun using sapply() and return object > sapply(index.list, function(i) > { > do.call(fun, list(x[, i], ...)) > }) > } > > ## Compute annual means > y <- byapply(df, 12, rowMeans) > > How can I switch rowMeans with a command that takes the maximum? I am a bit > baffled. Any help will be appreciated. Thank you. > > Sincerely, > > Milu > > ### > dput(droplevels(head(x, 5))) > structure(list(X0 = c(295.812103271484, 297.672424316406, 299.006805419922, > 297.631500244141, 298.372741699219), X1 = c(295.361328125, > 297.345092773438, > 298.067504882812, 297.285339355469, 298.275268554688), X2 = > c(294.279602050781, > 296.401550292969, 296.777984619141, 296.089111328125, 297.540374755859 > ), X3 = c(292.103118896484, 294.253601074219, 293.773803710938, > 293.916229248047, 296.129943847656), X4 = c(288.525024414062, > 291.274505615234, 289.502777099609, 290.723388671875, 293.615112304688 > ), X5 = c(286.018371582031, 288.748565673828, 286.463134765625, > 288.393951416016, 291.710266113281), X6 = c(285.550537109375, > 288.159149169922, 285.976501464844, 287.999816894531, 291.228271484375 > ), X7 = c(289.136962890625, 290.751159667969, 290.170257568359, > 291.796203613281, 293.423248291016), X8 = c(292.410003662109, > 292.701263427734, 294.25244140625, 295.320404052734, 295.248199462891 > ), X9 = c(293.821655273438, 294.139068603516, 296.630157470703, > 296.963531494141, 296.036224365234), X10 = c(294.532531738281, > 295.366607666016, 297.677551269531, 296.715911865234, 296.564178466797 > ), X11 = c(295.869476318359, 297.010070800781, 299.330169677734, > 297.627593994141, 297.964935302734), X12 = c(295.986236572266, > 297.675567626953, 299.056671142578, 297.598907470703, 298.481842041016 > ), X13 = c(295.947601318359, 297.934448242188, 298.745391845703, > 297.704925537109, 298.819091796875), X14 = c(294.654327392578, > 296.722717285156, 297.0986328125, 296.508239746094, 297.822021484375 > ), X15 = c(292.176361083984, 294.49658203125, 293.888305664062, > 294.172149658203, 296.117095947266), X16 = c(288.400726318359, > 291.029113769531, 289.361907958984, 290.566772460938, 293.554016113281 > ), X17 = c(285.665222167969, 288.293029785156, 286.118957519531, > 288.105285644531, 291.429382324219), X18 = c(285.971252441406, > 288.3798828125, 286.444580078125, 288.495880126953, 291.447326660156 > ), X19 = c(288.79296875, 290.357543945312, 289.657928466797, > 291.449066162109, 293.095275878906), X20 = c(291.999877929688, > 292.838348388672, 293.840362548828, 294.412322998047, 294.941253662109 > ), X21 = c(293.615447998047, 294.028106689453, 296.072296142578, > 296.447387695312, 295.824615478516), X22 = c(294.719848632812, > 295.392028808594, 297.453216552734, 297.114288330078, 296.883209228516 > ), X23 = c(295.634429931641, 296.783294677734, 298.592346191406, > 297.469512939453, 297.832122802734)), .Names = c("X0", "X1", > "X2", "X3", "X4", "X5", "X6", "X7", "X8", "X9", "X10", "X11", > "X12", "X13", "X14", "X15", "X16", "X17", "X18", "X19", "X20", > "X21", "X22", "X23"), row.names = c(NA, 5L), class = "data.frame") > > <https://www.avast.com/sig-email?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=webmail> > Mail > priva di virus. www.avast.com > <https://www.avast.com/sig-email?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=webmail> > <#DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2> > > [[alternative HTML version deleted]] > > ______________________________________________ > R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide http://www.R-project.org/posting-guide.html > and provide commented, minimal, self-contained, reproducible code. ______________________________________________ R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.