将平均列添加到 R 中的表数据框

Question

我有一个数据框，例如：

   COL1 VALUE1 VALUE2
1   A,A      1      5
2 A,A,B      1      3
3     C      1      1
4     D      1      2
5     D      1      2
6   A,A      1     10
7 A,B,A      1      2

我可以成功删除 COL1 中的重复项，并使用以下方法计算 COL1 中不同重复项的数量：

as.data.frame(table(tab$COL1)) %>%
  group_by(Var1 = sapply(strsplit(as.character(Var1), ","), function(x) toString(unique(x)))) %>%
  summarise(Freq = sum(Freq))

然后我得到：

# A tibble: 4 × 2
  Var1   Freq
  <chr> <int>
1 A         2
2 A, B      2
3 C         1
4 D         2

但我想知道是否有人想添加一个名为 Mean 的新列，这将是每个 COL1 groups，VALUE2 值的平均值，然后得到：

  Var1      Freq  Mean 
1 A         2     7.5   < because (5+10)/2 =7.5
2 A, B      2     2.5   < because (3+2)/2 =2.5 
3 C         1     1     < because 1/1 = 1 
4 D         2     2     < because (2+2)/2 = 2

如果有帮助，这里是数据框：

structure(list(COL1 = structure(c(1L, 2L, 4L, 5L, 5L, 1L, 3L), .Label = c("A,A", 
"A,A,B", "A,B,A", "C", "D"), class = "factor"), VALUE1 = c(1L, 
1L, 1L, 1L, 1L, 1L, 1L), VALUE2 = c(5L, 3L, 1L, 2L, 2L, 10L, 
2L)), class = "data.frame", row.names = c(NA, -7L))

Answer 1

您可以直接在dplyr链中计算频率表，然后在summarise()调用中添加一个Mean = mean(VALUE2)。

即

tab %>%
    group_by(Var1 = sapply(strsplit(as.character(COL1), ","), function(x) toString(unique(x)))) %>%
    summarise(Freq = sum(VALUE1), Mean = mean(VALUE2))

# # A tibble: 4 x 3
#   Var1   Freq  Mean
#   <chr> <int> <dbl>
# 1 A         2   7.5
# 2 A, B      2   2.5
# 3 C         1   1  
# 4 D         2   2 

Answer 2

这是你想要的吗：

library(dplyr)
tab %>%
  mutate(COL1 = sapply(strsplit(as.character(COL1), ","), function(x) toString(unique(x)))) %>%
  group_by(COL1) %>%
  summarise(Freq = sum(VALUE1),
            Mean = mean(VALUE2))
# A tibble: 4 x 3
  COL1   Freq  Mean
* <chr> <int> <dbl>
1 A         2   7.5
2 A, B      2   2.5
3 C         1   1  
4 D         2   2