Question

我看过类似的帖子，但没有任何工作可做。

我有一个字符1,2,3,4,5的列，它是面试问题的答案我想要一个新列，当响应为1或2时，新列为No，当响应为3时，新列为Partly，当响应为4或5为Yes时，所有其他都为NA。

data.frame':    405 obs. of  1 variables:
$ SQ023A        : chr  "-3" "-3" "-3" "-3" ...(this has -1, -2, -3, -4, 1, 2, 3, 4, 5, Yes, No, Partly)

新列应该保留Yes，No，Partly答案，但是将No和4和5替换为1和2，使用Partly替换3和3。其他一切都是NA。

我尝试了以下内容但没有成功

sq23$test <- ifelse(("1"|"2", sq23$SQ23A), "No",
             ifelse("4"|"5", sq23$SQ23A), "Yes",
             ifelse("3", sq23$SQ23A), "Partly","NA"))

Answer 1

尝试：

   sq23$test <- c("No","No","Partly","Yes","Yes")[as.numeric(sq23$SQ23A)]

编辑：

根据您的编辑，我将为这类问题提供更通用的解决方案。首先，我们构建一个包含我们要替换的旧值的向量。然后，我们定义另一个有替换的向量。然后我们通过match函数来完成这个技巧。例如：

    #create a sample of your data 
    sq23<-data.frame(SQ023A=sample(c(-4:5,"Yes","No","Partly"),size=405,replace=TRUE))
    #define the old values to replace
    oldValues<-c(1:5,"Yes","No","Partly")
    #define the replacement (each value of newValues replace the corresponding of oldValues)
    newValues<-c("No","No","Partly","Yes","Yes","Yes","No","Partly")
    #create the test column
    sq23$test<-newValues[match(sq23$SQ023A,oldValues)]

Answer 2

为清楚起见，我会这样做：

sq23$test<- NA
sq23$test[sq23$SQ23A == 1 | sq23$SQ23A == 2]<- "No"
sq23$test[sq23$SQ23A == 4 | sq23$SQ23A == 5]<- "Yes"
sq23$test[sq23$SQ23A == 3]<- "Partly"

根据您的编辑，对于更一般的情况，您还可以使用字典类型解决方案：

values<- c("no", "no", "partly","yes","yes","yes","no","partly")  # new value
names(values)<- c(1:5, "yes", "no", "partly")   # keys
> values
       1        2        3        4        5      yes       no   partly 
     "no"     "no" "partly"    "yes"    "yes"    "yes"     "no" "partly" 
sq23$test<- values[as.character(sq23$SQ23A)]  
# as.character() used to make sure that the keys/old values are passed as 
# characters, and not e.g. a factor

根据R中的其他列创建新的数据框列

2 个答案: