A named numeric vector of the requested confusion matrix metrics.
Values are generally in \([0, 1]\), with the exception of "mcc"
(Matthews Correlation Coefficient), which ranges from \(-1\) to \(1\)
where 1 indicates perfect agreement, 0 indicates chance-level performance,
and -1 indicates perfect disagreement. The vector contains only the elements
specified by metric (all ten metrics when metric = "all",
which is the default). Names are abbreviated (e.g., "sen") when
full.names = FALSE (default), or expanded
(e.g., "Sensitivity") when full.names = TRUE. Any metric
whose denominator is zero (e.g., sensitivity when no edges exist in
base) is returned as NA.