检查值是否在r数据帧中的值数组中

Question

我有一个包含两列Fruits和Groups的数据框。 我想检查Fruits的值是否为Groups的数组。 如果是，则改变新字段并添加是或否。

df <- data.frame(Fruits = c("Apple","Banana","Orange","Kiwi"),
                 Group = I(list(c("Apple","Strawberry"), 
                                c("Orange","Kiwi"),
                                c("Apple","Banana"),
                                c("Apple","Kiwi")
                                )))

df$Fruits %in% df$Group

Answer 1

由于Group是一个列表，我们无法直接比较它。 一种方法是使用mapply

df$Present <- c("No", "Yes")[mapply(`%in%`, df$Fruits, df$Group) + 1]

df
#  Fruits        Group Present
#1  Apple Apple, S....     Yes
#2 Banana Orange, Kiwi      No
#3 Orange Apple, B....      No
#4   Kiwi  Apple, Kiwi     Yes

mapply返回TRUE / FALSE值，然后我们使用索引技术得到Yes / No 。

mapply(`%in%`, df$Fruits, df$Group)
#[1]  TRUE FALSE FALSE  TRUE

---

或者类似于purrr map2_lgl

library(dplyr)
library(purrr)

df %>%
  mutate(Present = c("No", "Yes")[map2_lgl(Fruits, Group, `%in%`) + 1])

Answer 2

我们可以用

library(data.table)
setDT(df)[, Present := unlist(Map(`%in%`, Fruits, Group))]