explicit_grouping: Build a grouping triple from an explicit c(part, cnt) entry
Description
Internal constructor used by resolve_one_grouping() for the explicit
two-element form of a by entry, e.g. c(part = "X", cnt = "Y"). The
grouping's name is the participant column with any leading "part_"
stripped.
Usage
explicit_grouping(entry)
Value
a list(name, part, cnt) triple
Arguments
entry
a named two-element character vector with names "part"
and "cnt"