Examples:
print(match(5, c(1,2,9,5,3,6,7,4,5)))
[1] 4
5 %in% c(1,2,9,5,3,6,7,4,5)
[1] TRUE
8 %in% c(1,2,9,5,3,6,7,4,5)
[1] FALSE
> v1 <- c("a1","b2","c1","d2")
> v2 <- c("g1","x2","d2","e2","f1","a1","c2","b2","a2")
> x <- match(v1,v2)
> x
[1] 6 8 NA 3
> v1 <- c("a1","b2","c1","d2")
> v2 <- c("g1","x2","d2","e2","f1","a1","c2","b2","a2")
> v1 %in% v2
[1] TRUE TRUE FALSE TRUE
> v1 <- c("a1","b2","c1","d2")
> v2 <- c("g1","x2","d2","e2","f1","a1","c2","b2","a2")
> x <- match(v1,v2, nomatch = 0)
> x
[1] 6 8 0 3
> v1 <- c("a1","b2","c1","d2")
> v2 <- c("g1","x2","d2","e2","f1","a1","c2","b2","a2")
> x <- match(v1,v2, nomatch = 0, incomparables = "a1")
> x
[1] 0 8 0 3
ref:
https://www.r-bloggers.com/match-function-in-r/
原文：https://www.cnblogs.com/emanlee/p/8965683.html