Dataframe 如果满足条件，则重命名特定列中某行的某些值

如果某行的某个值符合某个if语句，如何重命名该列中的某个值

例如：

    Date    Type   C1 
    2000    none    3
    2000    love    4
    2000    none    6
    2000    none    2
    2000    bad     8

所以我想把我列类型中的“love”和“bad”重命名为“xxx”

有什么好办法吗

---

谢谢：）

首先，确保它不是一个因素，然后重命名：

df$Type = as.character(df$Type)
df$Type[df$Type %in% c("love", "bad")] = "xxx"

---

如果数据是因子，则需要重命名因子级别。最简单的方法是使用

forcats

包中的

fct\u recode（）

。如果它是一个字符向量，

ifelse

如果更改的数量很小，则效果很好。如果它很大，

dplyr

包中的

case_

运行良好

library(forcats)
library(dplyr)

df <- within(df, { # if you use `dplyr`, you can replace this with mutate.  You'd also need to change `<-` to `=` and add `,` at the end of each line.  
  Type_fct1 <- fct_recode(Type, xxx = "love", xxx = "bad")
  # in base R, you need can change the factor labels, but its clunky
  Type_fct2 <- Type
  levels(Type_fct2)[levels(Type_fct2) %in% c("love", "bad")] <- "xxx"

  # methods using character vectors
  Type_chr1 <- ifelse(as.character(Type) %in% c("love", "bad"), "xxx", as.character(Type))
  Type_chr2 <- case_when(
    Type %in% c("love", "bad") ~ "xxx",
    Type == "none" ~ "something_else", # thrown in to show how to use `case_when` with many different criterion.
    TRUE ~ NA_character_
  )

})

库（用于猫）
图书馆（dplyr）
df如果您使用的是data.table，您可以执行以下操作：
df[在%c中键入%s（'love'，'bad），键入：='xxx']
library(forcats)
library(dplyr)

df <- within(df, { # if you use `dplyr`, you can replace this with mutate.  You'd also need to change `<-` to `=` and add `,` at the end of each line.  
  Type_fct1 <- fct_recode(Type, xxx = "love", xxx = "bad")
  # in base R, you need can change the factor labels, but its clunky
  Type_fct2 <- Type
  levels(Type_fct2)[levels(Type_fct2) %in% c("love", "bad")] <- "xxx"

  # methods using character vectors
  Type_chr1 <- ifelse(as.character(Type) %in% c("love", "bad"), "xxx", as.character(Type))
  Type_chr2 <- case_when(
    Type %in% c("love", "bad") ~ "xxx",
    Type == "none" ~ "something_else", # thrown in to show how to use `case_when` with many different criterion.
    TRUE ~ NA_character_
  )

})