r - 如何折叠 R 中分类变量的水平

Question

我有各种分类变量，每个分类变量都超过 5 个级别，我想要一个可以将它们折叠成两个级别的函数

column1<- c("bad","good","nice","fair","great","bad","bad","good","nice",
            "fair","great","bad")
column2<- c("john","ben","cook","seth","brian","deph","omar","mary",
            "frank","boss","kate","sall")

df<- data.frame(column1,column2)

所以对于上面的数据框，在 column1 中，我想用一个函数将所有“bad”转换为“bad”，将其他级别转换为“others”。我不知道该怎么做。谢谢

Answer 1

使用ifelse 或case_when

library(dplyr)
df <- df %>% 
   mutate(column1 = case_when(column1 != "bad" ~ "others", TRUE ~ column1))

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此外，由于只有一个变化，我们可以这样做

df$column1[df$column1 != "bad"] <- "others"