match() and %in%

• match() returns the indices of elements in x that have matching values in table

table <- sample(c(1:10, NA), size = 100, replace = TRUE)
x <- c(5, 6, NA)
# returns indices in table
match(x, table, nomatch = 0)

## [1] 24 23  7

• %in% is an intuitive wrapper that returns a logical vector instead

# returns logical in x
x %in% table

## [1] TRUE TRUE TRUE