按组对值进行排序和连接 [英] Sort and concatenate values by group

问题描述

我有一个组和名称列表，如下面的 DF 所示.我希望按字母顺序排列这个列表，并连接由逗号分隔的每个名称，如下面的 DF2 所示.我以为这很简单，但事实证明它比预期的更具挑战性！

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"))

对于解决这个问题的任何帮助，无论是否有 dplyr 管道，我都会感谢每个组列出的未知数量的名称.

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.

谢谢！

推荐答案

我们可以使用data.table

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

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