You can either use function match or position, both of these works well in finding the index of an element in a vector.
For multiple matching use %in% as match only returns the first encounter of a match, this will help you with your problem.
Match returns the position in the second argument of the values in the first argument.
x <- sample(1:10)
x
# [1] 4 5 9 3 8 1 6 10 7 2
match(E(4,8),Q)
# [1] 1 5
In case of multiple matching %in% returns a logical value in case of first argument, with a TRUE if the value is in second argument, if not it returns a FALSE.
Q <- sample(1:4,10,replace=TRUE)
Q
# [1] 3 4 3 3 2 3 1 1 2 2
which(Q %in% E(2,4))
# [1] 2 5 9 10
Position allows the user to pass an arbitrary function, and returns the first or last match.
Position(G, Q, right = FALSE, nomatch = NA_integer)
You can ask your doubts in comments. Happy Learning....!!
