RandomKSubset[l, k] gives a random subset of set l with exactly k elements.

RandomPartition[n] constructs a random partition of integer n.

RandomPermutation[n] generates a random permutation of the first n natural numbers.

RandomTableau[p] constructs a random Young tableau of shape p.

RankGraph[g, l] partitions the vertices into classes based on the shortest geodesic distance to a member of list l.

RankPermutation[p] gives the rank of permutation p in lexicographic order.

ReflexiveQ[g] yields True if the adjacency matrix of g represents a reflexive binary relation.

RevealCycles[p] unveils the canonical hidden cycle structure of permutation p.

ReverseEdges[g] flips the directions of all edges in a directed graph.

SignaturePermutation[p] gives the signature of permutation p.