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
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