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/