Difference between the == and %in% operators in R [duplicate]

Answer 1

Try it for objects of different length.

ac <- c("a", "b", "c")
ae <- c("a", "b", "c", "d", "e")
ac %in% ae
[1] TRUE TRUE TRUE
ac == ae
[1]  TRUE  TRUE  TRUE FALSE FALSE

It's becomes clear that %in% checks whether or not the object is contained in the other object. Whereas == is a logical operator that checks for identity properties.