Returns a row for unpack_slope()
.
unpack_slope_term(term, i, last_slope, ttype = "")
A character, e.g., "x", "I(x^2)", or "log(x)".
Segment number (integer)
The element in the slope column for this ttype in the previous segment. I.e., probably what this function returned last time it was called!
The term type. One of "ct" (central tendency), "sigma" (variance), or "ar" (autoregressive)
A "one-row" list describing a slope term.