如何折叠R中分类变量的水平

aelbi1ox 于 2022-12-20 发布在其他

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我有多个分类变量，每个变量都有5个以上的水平，我需要一个函数，可以将它们折叠成两个水平

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，我想用一个函数把所有的“bad”转换成“bad”，把其他级别转换成“others”。我不知道该怎么做。谢谢

来源：https://stackoverflow.com/questions/74788905/how-to-collapse-levels-in-a-categorical-variable-in-r

4条答案

按热度按时间

csga3l581#

使用ifelse或case_when

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

另外，由于只有一个变化，我们可以只做

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

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oxosxuxt2#

在以R为基数的情况下，一个简单的方法是使用索引：

c('others', 'bad')[(df$column1 == 'bad') + 1]
#> [1] "bad"    "others" "others" "others" "others" "bad"    "bad"   
#> [8] "others" "others" "others" "others" "bad"

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hs1ihplo3#

df<- data.frame(factor=as.factor(column1),column2)
levels(df$factor)<-c("bad",rep("other",4))

赞(0）回复(0）举报 2022-12-20

62o28rlo4#

下面是带分组的dplyr解决方案：

library(dplyr)
df %>% 
  group_by(group = cumsum(column1=="bad")) %>% 
  mutate(column1 = ifelse(row_number()==1, "bad", "others")) %>% 
  ungroup() %>% 
  select(-group)

column1 column2
   <chr>   <chr>  
 1 bad     john   
 2 others  ben    
 3 others  cook   
 4 others  seth   
 5 others  brian  
 6 bad     deph   
 7 bad     omar   
 8 others  mary   
 9 others  frank  
10 others  boss   
11 others  kate   
12 bad     sall

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如何折叠R中分类变量的水平

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