Compares the equality of optmatch objects, ignoring attributes and group names.Source:
This checks the equality of two optmatch objects. The only bits that matter are unit names and the grouping. Other bits such as attributes, group names, order, etc are ignored.
The names of the units can differ on any unmatched units, e.g., units whose value in the optmatch
NA. If matched objects have differing names, this is automatically
Note this ignores the names of the subgroups. So four members in subgroups either
c("a", "a", "b", "b") or
c("b", "b", "a", "a") would be identical to this call.