排列或dcast并填写计数

可能是个基本问题。

我有一个 key - value data.frame ( df (见下文):

features <- paste0("f",1:5)
set.seed(1)
ids <- paste0("id",1:10)

df <- do.call(rbind,lapply(ids,function(i){
  data.frame(id = i, feature = sample(features,3,replace = F))
}))

我想 tidyr::spread 或 reshape2::dcast 将其删除,以便行被删除 id' the columns are 特色 , but the values are the sum of 特征 for each id`。

reshape2::dcast(df, id ~ feature)

但这并不能实现。它只是充满了 feature NA

添加 fun.aggregate = sum 对上面的命令执行以下操作会导致错误:

> reshape2::dcast(df, id ~ feature, fun.aggregate = sum)
Using feature as value column: use value.var to override.
Error in .fun(.value[0], ...) : invalid 'type' (character) of argument

tidyr::spread(df, key = id, value = feature)

Error: Each row of output must be identified by a unique combination of keys.
Keys are shared for 30 rows:

有什么想法吗?