r - 按组划分的独特词

Question

这是我的示例数据框

example = data.frame(group = c("A", "B", "A", "A"), word = c("car", "sun ,sun, house", "car, house", "tree"))

我只想在组内和组内获得唯一的词

所以我想得到这个

group   word
A       car, tree
B       sun

我使用聚合并得到这个

aggregate(word ~ group , data = example,  FUN = paste0) 

  group                  word
1     A car, car, house, tree
2     B       sun ,sun, house

但现在我只需要选择唯一值，但即使这样也行不通

for (i in 1:nrow(cluster)) {cluster[i, ][["word"]] = lapply(unlist(cluster[i, ][["word"]]), unique)}

与

Error in `[[<-.data.frame`(`*tmp*`, "word", value = list("car", "car, house",  : 
  replacement has 3 rows, data has 1

Answer 1

使用 aggregate + subset + ave 的基本 R 选项，如下所示

with(
  aggregate(
    word ~ .,
    example,
    function(x) {
      unlist(strsplit(x, "[, ]+"))
    }
  ),
  aggregate(
    . ~ ind,
    subset(
      unique(stack(setNames(word, group))),
      ave(seq_along(ind), values, FUN = length) == 1
    ),
    c
  )
)

给予

  ind    values
1   A car, tree
2   B       sun