Sort and concatenate values by group

Question

I've got a list of Groups and Names, as seen in DF below. I'm looking to arrange this list alphabetically and concatenate each name separated by a comma, as seen in DF2 below. I thought this would be simple, but it is proving to be more challenging than expected!

DF <- tibble::data_frame(
    Group = c(1, 1, 1, 2, 2, 3, 3, 3), 
    Name = c("A", "B", "C", "B", "A", "B", "C", "A"))

DF2 <- tibble::data_frame(
    Group = c(1, 2, 3), 
    Name = c("A, B, C", "A, B", "A, B, C"))

I'd appreciate any help in solving this to account for an unknown number of names listed per group, either with or without a dplyr pipeline.

Thanks!

How is `DF %>% group_by(Group) %>% summarize(Comb = paste(Name[order(Name)], collapse = ","))`? — Abdou, Oct 28 '16 at 15:33
@Abdou Or `DF %>% arrange(Name) %>% group_by(Group) %>% summarize(Comb = toString(Name))` — Frank, Oct 28 '16 at 15:35

score 3 · Accepted Answer · answered Oct 28 '16 at 15:37

3

We can use data.table

library(data.table)
setDT(DF)[order(Name), .(Comb = toString(Name)) , by = Group]

answered Oct 28 '16 at 15:37

akrun

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score 3 · Answer 2 · answered Oct 28 '16 at 15:41

3

In base R:

aggregate(Name~Group, DF, function(x) paste0(sort(x), collapse = ","))

#  Group  Name
#1     1 A,B,C
#2     2   A,B
#3     3 A,B,C

answered Oct 28 '16 at 15:41

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Sort and concatenate values by group

2 Answers2

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