r - 计算每年销售额的 Top N 产品

Question

我有关于年销售额和副产品的数据，我们可以这样说:

Year <- c(2010,2010,2010,2010,2010,2011,2011,2011,2011,2011,2012,2012,2012,2012,2012)
Model <- c("a","b","c","d","e","a","b","c","d","e","a","b","c","d","e")
Sale <- c("30","45","23","33","24","11","56","19","45","56","33","32","89","33","12")
df <- data.frame(Year, Model, Sale)

我想要按年份标识前 2 名产品并将所有其余产品汇总为类别“其他”的代码。

Answer 1

我们可以按desc结束顺序按'Year'和'Sale'排列，然后在按'Year'分组后根据row_number更改'Model'的值'

library(dplyr)
df %>% 
 arrange(Year, desc(Sale)) %>% 
 group_by(Year) %>%
 mutate(Model = case_when(row_number() > 2~ 'other', TRUE ~ Model)) %>%
 ungroup

---

或者另一种选择是使用slice_max(默认情况下with_ties = TRUE)

df %>%
  group_by(Year) %>% 
  mutate(Model =case_when(Model %in% {cur_data() %>% 
     slice_max(n = 2, order_by = Sale) %>%
     pull(Model)} ~ Model, TRUE ~ "other" )
)