我试图在小标题中生成随机数，其中不同类别的项目分布不同。我运气不太好。这是代码及其产生的错误：
\nlibrary(dplyr)\n\nletters <- tibble(letter = c(rep("A", 5), rep("B", 5), rep("C", 5) ))\n\nletters %>%\n rowwise() %>%\n mutate(Proj = case_when(\n letter == "A" ~ rpois(1, lambda = .7746),\n letter == "B" ~ rnbinom(1, size = 3.3848, mu = 1.2),\n letter == "C" ~ rpois(1, lambda = .5057)\n ))\n\n#> Error in `mutate()`:\n#> ! Problem while computing `Proj = case_when(...)`.\n#> \xe2\x84\xb9 The error occurred in row 1.\n#> Caused by error in `` names(message) <- `*vtmp*` ``:\n#> ! \'names\' attribute [1] must be the …