The input graph, it can be directed or undirected.

Vector giving the vertex types. They as assumed to be integer numbers, starting with one. Non-integer values are converted to integers with as.integer().

Logical scalar, whether to consider edge directions for directed graphs. This argument is ignored for undirected graphs. Supply TRUE here to do the natural thing, i.e. use directed version of the measure for directed graphs and the undirected version for undirected graphs.

Boolean, whether to compute the normalized assortativity. The non-normalized nominal assortativity is identical to modularity. The non-normalized value-based assortativity is simply the covariance of the values at the two ends of edges.