dplyr，总结分类变量

Question

我想总结一下我的数据small ，使用各种不同video.id dplyr 。

small %>% 
  group_by(Video.ID) %>% 
  summarise(sumr = sum(Partner.Revenue),
            len = mean(Video.Duration..sec.),
            cat = mean(Category))

均值（类别）显然是错误的做法。 我如何才能使用重复多次的值（一个video.id始终是相同的类别，无论它在数据帧中出现的频率如何）。

我的数据框看起来像这样：

small

# A tibble: 6 x 7
     X1  X1_1 Video.ID    Video.Duration..sec. Category Owned.Views Partner.Revenue
  <int> <int> <chr>                      <int> <chr>          <int>           <dbl>
1     1     1 ---0zh9uzSE                 1184 gadgets            6               0
2     2     2 ---0zh9uzSE                 1184 gadgets            6               0
3     3     3 ---0zh9uzSE                 1184 gadgets            2               0
4     4     4 ---0zh9uzSE                 1184 gadgets            1               0
5     5     5 ---0zh9uzSE                 1184 gadgets            1               0
6     6     6 ---0zh9uzSE                 1184 gadgets            3               0

small <- 
  structure(list(X1 = 1:6, 
                 X1_1 = 1:6, 
                 Video.ID = c("---0zh9uzSE", "---0zh9uzSE", "---0zh9uzSE", "---0zh9uzSE", "---0zh9uzSE", "---0zh9uzSE"), 
                 Video.Duration..sec. = c(1184L, 1184L, 1184L, 1184L, 1184L, 1184L), 
                 Category = c("gadgets", "gadgets", "gadgets", "gadgets", "gadgets", "gadgets"), 
                 Owned.Views = c(6L, 6L, 2L, 1L, 1L, 3L), 
                 Partner.Revenue = c(0, 0, 0, 0, 0, 0)), 
            row.names = c(NA, -6L), 
            class = c("tbl_df", "tbl", "data.frame"))

Answer 1

您至少有两个选项可以解决此问题：

将Category列添加到group_by ：

small %>% 
  group_by(Video.ID, cat = Category) %>% 
  summarise(sumr = sum(Partner.Revenue),
            len = mean(Video.Duration..sec.))

# A tibble: 1 x 4
# Groups:   Video.ID [?]
#     Video.ID    cat      sumr   len
#     <chr>       <chr>   <dbl> <dbl>
#   1 ---0zh9uzSE gadgets     0  1184

或使用unique(Catregory) ：

small %>% 
  group_by(Video.ID) %>% 
  summarise(sumr = sum(Partner.Revenue),
            len = mean(Video.Duration..sec.),
            cat = unique(Category))

# A tibble: 1 x 4
#   Video.ID     sumr   len cat    
#   <chr>       <dbl> <dbl> <chr>  
# 1 ---0zh9uzSE     0  1184 gadgets

第一个选项可能是允许的，因为如果每个ID有多个类别，它仍然有效。

Answer 2

由于它是每个video_id的唯一类别，因此您可以使用cat = Category[1] ，如

small %>% group_by(Video.ID) %>% 
      summarise(sumr=sum(Partner.Revenue), len = mean(Video.Duration..sec.), 
      cat = Category[1])

# A tibble: 1 x 4
#  Video.ID     sumr   len cat    
#  <chr>       <dbl> <dbl> <chr>  
#  1 ---0zh9uzSE     0  1184 gadgets