Parse Prader bead ml thresholds from tv reference column names

Internal helper shared by calculate_sds and snap_tv_to_nearest_bead: both need the raw ml threshold each "T"-prefixed tv reference column represents (e.g. "T12" -> 12), though what they do with those thresholds afterward differs (bracket-and-interpolate vs. snap-to-nearest).

Usage

tv_ml_thresholds(colnames)

Arguments

colnames

Character vector of "T"-prefixed column names (e.g. "T1", "T2", ..., "T25"), as found in ref$tv (see nl1997/nl1997_lines), with any leading "age" column already excluded.

Value

Numeric vector the same length as colnames: the ml threshold each column represents.