“Group_by_at & Group_by”杂志

Question

下面是我想要执行的数据框架和代码。如下面所示，我想要group_by x以及color。x是一个字符串，因此我使用了group_by_at函数。

df <- data.frame(
        color = c("Yellow", "Blue", "Green", "Red", "Magenta"),
        values = c(24, 24, 34, 45, 49),
        Quarter = c("Period1","Period2" , "Period3", "Period3", "Period1"),
        Market = c("Camden", "StreetA", "DansFireplace", "StreetA", "DansFireplace"))
    
list = c("Market", "Quarter")

df_all <- do.call(rbind, lapply(list, function(x) {
    df_l <- df %>% 
              group_by_at(x) %>% 
              group_by(color) %>%
              summarise(values = sum(values)) %>% 
              mutate(cut = x) %>% 
              data.frame()
    colnames(df_l)[colnames(df_l) == x] <- "Grouping"
    df_l
}))

问题是，在运行此代码时，它不是按x分组的。只有当我删除group_by(color)时，它才会按x分组。

我的目标是同时按x和color进行分组。

Answer 1

如果我正确理解了您的问题，请将color和x包含在同一个group_by语句中：

df_all <- do.call(rbind, lapply(list, function(x){
  df_l= df %>% group_by_at(c(x, "color")) %>% 
    summarise(values = sum(values)) %>% 
    mutate(cut= x) %>% 
    data.frame()
  colnames(df_l)[colnames(df_l)==x] <- "Grouping"
  df_l
}))

这意味着：

        Grouping   color values     cut
1         Camden  Yellow     24  Market
2  DansFireplace   Green     34  Market
3  DansFireplace Magenta     49  Market
4        StreetA    Blue     24  Market
5        StreetA     Red     45  Market
6        Period1 Magenta     49 Quarter
7        Period1  Yellow     24 Quarter
8        Period2    Blue     24 Quarter
9        Period3   Green     34 Quarter
10       Period3     Red     45 Quarter