不同载体中的常见和独特元素

Question

我有两个字符串向量，我想返回它们共有的内容以及向量a和向量b的唯一内容。

Vector

Answer 1

正如@David Arenburg的评论中已经提到的，您可以在intersect中使用setdiff和base - R：

> a<- letters[seq( from = 1, to = 10 )]
> b<- letters[seq( from = 6, to = 15 )]
> a
 [1] "a" "b" "c" "d" "e" "f" "g" "h" "i" "j"
> b
 [1] "f" "g" "h" "i" "j" "k" "l" "m" "n" "o"
> intersect(a, b)
[1] "f" "g" "h" "i" "j"
> setdiff(a, b)
[1] "a" "b" "c" "d" "e"
> setdiff(b, a)
[1] "k" "l" "m" "n" "o"

Answer 2

共同要素：

a[a %in% b] # or b[b %in% a]
[1] "f" "g" "h" "i" "j"

独一无二：

a[!a %in% b] # or a[b %in% a]
[1] "a" "b" "c" "d" "e"

b独有：

b[!b %in% a] # or b[a %in% b]
[1] "k" "l" "m" "n" "o"

  

备注

值得指出的是，intersect和setdiff将丢弃参数中的任何重复值。而%in%将保留重复。因此，如果我们有重复的值，我们将得到不同的结果。例如，在向量a：

中生成重复元素 a

a <- c(a, "a")
[1] "a" "b" "c" "d" "e" "f" "g" "h" "i" "j" "a"
# Duplicated element a is discarded
setdiff(a, b)
[1] "a" "b" "c" "d" "e"
# Keeps duplicated element a
a[!a %in% b]
[1] "a" "b" "c" "d" "e" "a"