extract_ids: Extract and standardize IDs from data frames

In couplr: Optimal Pairing and Matching via Linear Assignment

Extract and standardize IDs from data frames

Description

The id a matching carries is the key every downstream verb joins on, so it is resolved once, here, and the same resolution answers match_couples() and join_matched(). id_col names the column to read; with no name given a column called id is used, then meaningful row names, then ids synthesized from prefix.

Usage

extract_ids(df, prefix = "id", id_col = NULL, warn_synthetic = FALSE)

Arguments

df	Data frame to read ids from.
prefix	Prefix for synthesized ids, also the side name used in messages ("left" / "right").
id_col	Name of the id column, or NULL to resolve one.
warn_synthetic	If TRUE, warn when ids are synthesized because no id column was named or found.

Details

Ids read from the data must be unique: a repeated value makes every id-keyed join downstream many-to-many, which expands rows and attaches one unit's covariates to another unit's pair. Synthesized ids are unique by construction and are not checked.

Value

Character vector of IDs.

couplr documentation built on Sept. 17, 2026, 1:08 a.m.