R 根据另一列的因子水平创建新的值列 [英] R Create new column of values based on the factor levels of another column

问题描述

我正在尝试根据另一列的值创建一个新的值列.如果 iucnStatus 列中的值是LC"或NT"，我希望新列(受威胁)中的值是Not_Threatened".如果 iucnStatus 中的值是VU"、EN"、CR"、EW"或EX"，我希望新列(受威胁)中的值是受威胁".我在编写创建新列的代码方面做到了这一点:

I am trying to create a new column of values based on the values of another column. If the values in column iucnStatus are "LC" or "NT" I want the value in the new column (threatened) to be "Not_Threatened". If the values in iucnStatus are "VU", "EN", "CR", "EW", or "EX" I want the value in the new column (threatened) to be "Threatened." I got this far in writing code to create the new column:

df<-read.csv('master2.csv')

df$threatened <-apply(df$iucnStatus, 1,function(x)

但我不确定要传递给 function(x) 的函数是什么.也对不使用应用功能的任何其他解决方案开放.

But I wasn't sure what function to pass into function(x). Also open to any other solutions that don't use the apply function.

推荐答案

如果你只有两种状态，你可以使用 ifelse.

You can use ifelseif you have only two types of status.

df$Threatened <- ifelse(df$iucnStatus %in% c("LC","NT"),"Not_Threatened", "Threatened")
#Without `ifelse`
#df$Threatened <- c("Threatened", "Not_Threatened")[(df$iucnStatus %in% c("LC","NT")+ 1)]

如果还有很多状态码要检查，可以使用case_when

If there are many more status codes that you want to check, you can use case_when

library(dplyr)

df %>%
  mutate(Threatened = case_when(
                        Status %in% c("LC","NT") ~ "Not_Threatened", 
                        Status %in% c("VU", "EN", "CR", "EW","EX") ~ "Threatened", 
                        #More conditions
         ))

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