Re: [Rd] seq_along and rep_along
hello folks [snip] but it is frustrating when base functionality only works with vectors, not matrices, or arrays. It would be more compelling if (e.g.) t and rev also had dimension arguments. Hadley -- well put! I would add, though, that t() generalizes to aperm(), and the magic package contains arev() which is a generalization of rev(). I'm always on the lookout for other array functionality of this type that might sit well with magic. Anyone? best wishes Robin Assistant Professor / Dobelman Family Junior Chair Department of Statistics / Rice University http://had.co.nz/ __ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel -- Robin Hankin Uncertainty Analyst hankin.ro...@gmail.com __ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
Re: [Rd] seq_along and rep_along
well put! I would add, though, that t() generalizes to aperm(), and the magic package contains arev() which is a generalization of rev(). There are the flip operators of matlab, and rotating matrices/array by multiples of 90 degrees. I'm always on the lookout for other array functionality of this type that might sit well with magic. Anyone? Have you considered pulling out the matric manipulation functions from magic? I think they'd do well in their own package, and would be more findable. Hadley -- Assistant Professor / Dobelman Family Junior Chair Department of Statistics / Rice University http://had.co.nz/ __ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
Re: [Rd] seq_along and rep_along
hello Hadley thanks for this... There are the flip operators of matlab, and rotating matrices/array by multiples of 90 degrees. arot() in the magic package does this (which is an operation frequently encountered in magic hypercubes) I'm always on the lookout for other array functionality of this type that might sit well with magic. Anyone? Have you considered pulling out the matric manipulation functions from magic? I think they'd do well in their own package, and would be more findable. That is a very good idea. I have fought shy of this because the array functionality of the magic package didn't seem to be enough to justify a package of its own, but maybe that isn't true any more. And I must say that the majority of user comments on the magic package are in relation to functions such as arot() and adiag() and apad() and aplus() etc etc that are not specific to magic hypercubes. Does the List have any comments? rksh Hadley -- Assistant Professor / Dobelman Family Junior Chair Department of Statistics / Rice University http://had.co.nz/ -- Robin Hankin Uncertainty Analyst hankin.ro...@gmail.com __ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
[Rd] seq_along and rep_along
Hi all, A couple of ideas for improving seq_along: * It would be really useful to have a second argument dim: seq_along(mtcars, 1) seq_along(mtcars, 2) # equivalent to seq_len(dim(mtcars)[1]) seq_len(dim(mtcars)[2]) I often find myself wanting to iterate over the rows or column of a data frame, and there isn't a particularly nice idiom if you want to avoid problems with zeros - you have to use seq_len(nrow(df)) etc * To me, it would seem be very natural to have a rep_along function: rep_along - function(x, y) rep(x, length.out = length(y)) possibly with more checking for the case where the lengths aren't integer multiples. I'd be happy to submit proposed implementations/documentation if there was interest. Hadley -- Assistant Professor / Dobelman Family Junior Chair Department of Statistics / Rice University http://had.co.nz/ __ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
Re: [Rd] seq_along and rep_along
On 12-01-06 1:31 PM, Hadley Wickham wrote: Hi all, A couple of ideas for improving seq_along: * It would be really useful to have a second argument dim: seq_along(mtcars, 1) seq_along(mtcars, 2) # equivalent to seq_len(dim(mtcars)[1]) seq_len(dim(mtcars)[2]) I often find myself wanting to iterate over the rows or column of a data frame, and there isn't a particularly nice idiom if you want to avoid problems with zeros - you have to use seq_len(nrow(df)) etc I don't see the benefit of seq_along(mtcars, 1) versus seq_len(nrow(df)) in readability. Duncan Murdoch * To me, it would seem be very natural to have a rep_along function: rep_along- function(x, y) rep(x, length.out = length(y)) possibly with more checking for the case where the lengths aren't integer multiples. I'd be happy to submit proposed implementations/documentation if there was interest. Hadley __ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
Re: [Rd] seq_along and rep_along
I don't see the benefit of seq_along(mtcars, 1) versus seq_len(nrow(df)) in readability. I like it because: * it reads nicely: I want a sequence along this structure in that direction * it's more consistent: for(i in seq_along(x)) - for(row in seq_along(mtcars, 1)) * it generalised in a straightforward way to arrays I don't think it's a huge improvement, but it is frustrating when base functionality only works with vectors, not matrices, or arrays. It would be more compelling if (e.g.) t and rev also had dimension arguments. Hadley -- Assistant Professor / Dobelman Family Junior Chair Department of Statistics / Rice University http://had.co.nz/ __ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
