Strip the direction suffix from a CTD cast sample_key

CTD sample_keys end in the cast direction — …:cast:9802_008d / …:cast:9802_008u — so a station occupation that logged both directions is two sample rows sharing a base.

Usage

qc_cast_base(sample_key)

Arguments

sample_key

character vector of cast keys

Value

the keys with a single trailing d/u removed; keys without one are returned unchanged

Details

THE OBVIOUS IMPLEMENTATION IS WRONG. sub("d$", "", x) is fine, but gsub("d", "", x) or replace(x, 'd', '') also eats the d in the calcofi_ctd-cast prefix and silently returns a key that matches nothing. The same trap is called out in ctd_updown_disagreement.sql, which is where it was first hit.

Examples

qc_cast_base("calcofi_ctd-cast:cast:9802_008d")
#> [1] "calcofi_ctd-cast:cast:9802_008"