thank you for the help
this is my solution based on your valuable hint but without the need to pass
through the use of a 'tibble'
x<-data.frame(id=LETTERS[1:10], A=c(123,345,123,678,345,123,789,345,123,789))
uA<-unique(x$A)
idx<-lapply(uA, function(v) which(x$A %in% v))
vals<- lapply(idx, function(index) x$id[index])
data.frame(unique_A = uA, list_vals=unlist(lapply(vals, paste, collapse = ",
")))
best
Da: "Ben Tupper" <btup...@bigelow.org>
A: "Massimo Bressan" <massimo.bres...@arpa.veneto.it>
Cc: "r-help" <R-help@r-project.org>
Inviato: Giovedì, 7 giugno 2018 14:47:55
Oggetto: Re: [R] aggregate and list elements of variables in data.frame
Hi,
Does this do what you want? I had to change the id values to something more
obvious. It uses tibbles which allow each variable to be a list.
library(tibble)
library(dplyr)
x <- tibble(id=LETTERS[1:10],
A=c(123,345,123,678,345,123,789,345,123,789))
uA <- unique(x$A)
idx <- lapply(uA, function(v) which(x$A %in% v))
vals <- lapply(idx, function(index) x$id[index])
r <- tibble(unique_A = uA, list_idx = idx, list_vals = vals)
> r
# A tibble: 4 x 3
unique_A list_idx list_vals
<dbl> <list> <list>
1 123. <int [4]> <chr [4]>
2 345. <int [3]> <chr [3]>
3 678. <int [1]> <chr [1]>
4 789. <int [2]> <chr [2]>
> r$list_idx[1]
[[1]]
[1] 1 3 6 9
> r$list_vals[1]
[[1]]
[1] "A" "C" "F" "I"
Cheers,
ben
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