R语言if语句

有没有大佬可以帮我看看这个语句有什么问题呀？



setwd("D:/R_edu/data")
loans=read.csv("loans.csv")
if (loans$status == "A"){loans$bad_good <-0
}else if (loans$status == "B") {loans$bad_good <-1
}else if (loans$status == "D") {loans$bad_good <-1
}else{
  loans$bad_good <-NA
}

报错：
Warning messages:
1: In if (loans$status == "A") { :
  the condition has length > 1 and only the first element will be used
2: In if (loans$status == "B") { :
  the condition has length > 1 and only the first element will be used



谢谢大佬

1. for (i in 1:length(loans$status)){
   
2. if (loans$status[i] == "A") {loans$bad_good<-0}  #这里的bad_good变量是原数据集中就存在的吗？建议写成loans[, 'bad_good']
   
3. else if (loans$status[i] == "B") {loans$bad_good<-1}
   
4. else if (loans$status[i] == "D") {loans$bad_good<-1} #这里的赋值有重复
   
5. else {loans$bad_good<-NA}
   
6. }

复制代码

loans$status 是数据集中的一列变量的取值，理论上来说是向量或者1维的矩阵，这就需要使用循环，遍历这个向量或者1维矩阵的每一个元素，去判断是否等于 A 或者 B，所以建议使用 for 循环

Jasonbestone 发表于 2022-10-24 22:47
有没有大佬可以帮我看看这个语句有什么问题呀？

不写if语句也可以直接赋值的，如果写if语句的话，上面再这个循环才可以