使用

DF[DF$pets == "dog", c("color", "ID")] <- list("red", 1)

或执行连接

library(dplyr)
 left_join(DF, tibble(pets = "dog", color = "red", ID = 1))

技巧是用data.frame来merge。
您可以添加一行

d1 <- data.frame(pets='dog',
                 color='red', 
                 ID=1)

merge(DF, d1, all=TRUE)
#    pets names color ID
# 1  bird   sam  <NA> NA
# 2   cat   bob  <NA> NA
# 3   dog  john   red  1
# 4 horse  bill  <NA> NA
# 5 mouse frank  <NA> NA

和多行（即使DF中没有owl）。

d2 <- data.frame(pets=c('dog', 'bird', 'owl'),
                 color=c('red', 'green', 'blue'), 
                 ID=c(1, 2, 3))

merge(DF, d2, all=TRUE)
#    pets names color ID
# 1  bird   sam green  2
# 2   cat   bob  <NA> NA
# 3   dog  john   red  1
# 4 horse  bill  <NA> NA
# 5 mouse frank  <NA> NA
# 6   owl  <NA>  blue  3

数据框自动按pets合并，因为它是共享列名。查看?merge以获得其他选项。结果按pets按字母顺序排序，使用merge(., sort=FALSE)关闭该行为。

• 数据：*

DF <- structure(list(names = c("john", "bob", "frank", "bill", "sam"
), pets = c("dog", "cat", "mouse", "horse", "bird")), class = "data.frame", row.names = c(NA, 
-5L))