匹配数据框的多个列并替换值

Question

如何使用匹配的行替换NA中three列中的A值＆＃39; three中的B列中的值？

A
   one                 two three
1    A ram 1500 pickup 4wd     0
2    B               jetta     0
3    C         4runner 4wd  <NA>
4    D     mountaineer 4wd     5
5    E         range rover  <NA>
6    F ram 1500 pickup 4wd     0
7    G               jetta     0
8    H         4runner 4wd  <NA>
9    I     mountaineer 4wd     5
10   J         range rover     0
11   K ram 1500 pickup 4wd     0
12   L               jetta  <NA>
13   M         4runner 4wd     0
14   N     mountaineer 4wd     0
15   O         range rover  <NA>
16   P ram 1500 pickup 4wd     0
17   Q               jetta     5
18   R         4runner 4wd     5
19   S     mountaineer 4wd  <NA>
20   T         range rover  <NA>



B
   one             two three
3    C     4runner 4wd     1
5    E     range rover     1
8    H     4runner 4wd     1
12   L           jetta     1
15   O     range rover     1
19   S mountaineer 4wd     1
20   T     range rover     1

Answer 1

假设您的两个表都是数据框：

C <- merge(A, B, by = c("one", "two"), all.x = TRUE)
C$three.x <- ifelse(is.na(C$three.x), C$three.y, C$three.x)
C$three.y <- NULL
names(C)[3] <- "three"