按特定顺序设置因子水平[重复]

【问题标题】：set factor levels in specific order [duplicate]按特定顺序设置因子水平[重复]
【发布时间】：2021-11-07 16:45:46
【问题描述】：

如何按特定顺序设置级别？所需的级别顺序是 - "CA", "IN", "FL" "NY"

library(dplyr)

tbl <- tibble(states = c("FL", "NY", "CA", "IN")) %>%
  mutate(states_fct = factor(states))

【问题讨论】：

标签： r dplyr

【解决方案1】：

使用levels = 参数。

tbl <- tibble(states = c("FL", "NY", "CA", "IN")) %>%
  mutate(states_fct = factor(states, levels = c("CA", "IN", "FL", "NY"))

【讨论】：

【解决方案2】：

您可以使用ordered 表示您想要一个有序因子：

states = ordered(c("FL", "NY", "CA", "IN"), levels = c("CA", "IN", "FL", "NY"))
str(states)

【讨论】：

【解决方案3】：

我们可以使用来自forcats 包的fct_relevel：

library(dplyr)
library(forcats)
tbl <- tibble(states = c("FL", "NY", "CA", "IN")) %>%
    mutate(states_fct = factor(states)) %>% 
    mutate(states_fct = fct_relevel(states_fct, c("CA", "IN", "FL", "NY")))

levels(tbl$states_fct)

输出：

  states states_fct
  <chr>  <fct>     
1 FL     FL        
2 NY     NY        
3 CA     CA        
4 IN     IN        

> levels(tbl$states_fct)
[1] "CA" "IN" "FL" "NY"

【讨论】：