相关疑难解决方法(0)

在data.tableFAQ中,该nomatch = NA参数被称为类似于外连接.但是,我一直没能得到data.table做一个全外连接-只有右外连接.

例如:

a <- data.table("dog" = c(8:12), "cat" = c(15:19))

   dog cat
1:   8  15
2:   9  16
3:  10  17
4:  11  18
5:  12  19

b <- data.table("dog" = 1:10, "bullfrog" = 11:20)

    dog bullfrog
 1:   1       11
 2:   2       12
 3:   3       13
 4:   4       14
 5:   5       15
 6:   6       16
 7:   7       17
 8:   8       18
 9:   9       19
10:  10       20

setkey(a, dog) …