识别列中的多个字符串，然后在单独的列上输出观察结果； R v3.3.0

Question

我有一个示例数据，例如：

当前数据帧：

Person <- c("John","Jacob","Jill","Joan") 
Fruits <- c("Apples","Apples,Oranges","Bananas","Oranges,Bananas")
df <- as.data.frame(cbind(Person,Fruits))

我试图确定字符串中是否包含单个水果，然后将水果的名称放在单独的列中，如果苹果与其他水果一起列出，则 "Apple & Other"，或者如果有多个水果（不包括苹果）将其标识为 "Multiple"，如下所示：

想要输出：

Person <- c("John","Jacob","Jill","Joan")
Fruits <- c("Apples","Apples,Oranges","Bananas","Oranges,Apples,Bananas")
Fruits2 <- c("Apples","Apples & Other","Bananas","Multiple")
df2 <- cbind(Person,Fruits)
df2 <- as.data.frame(cbind(df2,Fruits2))

我试过使用以下 ifelse 语句：

df$Fruits2 <- ifelse(grep("\bApples\b",df$Fruits),"Apples",
                 ifelse(grep(".Apples.|.Apples|Apples.",df$Fruits),"Apples & Other",
                        ifelse(grep("\bOranges\b",df$Fruits),"Oranges",
                               ifelse(grep(".Oranges.|.Oranges|Oranges.",df$Fruits),"Multiple",
                                      ifelse(grep("\bBananas\b",df$Fruits),"Bananas",
                                             ifelse(grep(".Bananas.|.Bananas|Bananas.",df$Fruits),"Multiple","TBD"))))))

但是df$Fruits2的输出全部变成了Output。不知道是不是嵌套if语句的逻辑，如果有更好的解决办法，不胜感激。

Answer 1

这个 if-else 对于你的逻辑来说可能更简洁，通常你从大多数特定情况到更一般的情况，此外你将需要 grepl 其中 returns 逻辑值而不是 grep 其中 returns 整数或原始向量中的值：

library(dplyr)
df %>% mutate(Fruits2 = ifelse(grepl(",", Fruits), 
                        ifelse(grepl("Apples", Fruits), "Apples & Other", "Multiple"), 
                        Fruits))

#   Person          Fruits        Fruits2
# 1   John          Apples         Apples
# 2  Jacob  Apples,Oranges Apples & Other
# 3   Jill         Bananas        Bananas
# 4   Joan Oranges,Bananas       Multiple

Answer 2

您可以使用 strsplit() 在“,”上拆分，并使用 ifelse 验证条件并使用您需要的字符串保存在新列中。

  df$Fruits2 <- sapply(strsplit(df$Fruits,","),function(x){ifelse(length(x)==1,x[1], ifelse(length(x)>=2 & "Apples" %in% x, "Apples & Other","Multiple"))})

   df

   Person           Fruits         Fruits2
 1   John           Apples          Apples
 2  Jacob   Apples,Oranges  Apples & Other
 3   Jill          Bananas         Bananas
 4   Joan  Oranges,Bananas        Multiple

识别列中的多个字符串，然后在单独的列上输出观察结果； R v3.3.0

Identifying Multiple String in a Column then Outputting the Observation on a Separate Column; R v3.3.0

r

stringr