How can I get the complement of vector y in vector x

Question

That\'s x \\ y using mathematical notation. Suppose

x <- c(0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,1,2,1,1,1,3) 
y <- c(0,0,0,0,0,0,0,0,0,0,0,0,0,         


        

Answer 1

Here a solution using pmatch (this gives the "complement" as you require):

x <- c(0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,1,2,1,1,1,3)
y <- c(0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,1,1)
res <- x[is.na(pmatch(x,y))]

From pmatch documentation:

"If duplicates.ok is FALSE, values of table once matched are excluded from the search for subsequent matches."