Combinations

combinations(Integer, Integer)

combinations(List | Vector, Integer)

Given two integers $n$ and $k$, returns the number of ways to choose $k$ elements among $n$: $\binom{n}{k}$.

Given a list or vector $L$ and an integer $k$, returns a list with all the possible ways to choose $k$ element among $L$.

Binomial, Combinations with repetition, Variations, Variations with repetition