Read primary-key keys from a data.frame or sidecar/meta list

Extract the primary-key column names from either an in-memory data.frame (via the stamp_pk attribute) or from a sidecar/meta list (a previously recorded pk element). Returns an empty character vector when none is found.

Usage

st_get_pk(x_or_meta)

Arguments

x_or_meta

Either a data.frame (with attribute stamp_pk) or a sidecar/meta list as returned by st_read_sidecar().

Value

Character vector of primary-key column names (may be length 0).