Add a Prediction Blocking Rule

Adds an equality-based blocking rule to a specification. During prediction, only record pairs that agree on the blocking columns are scored. Multiple calls are OR-ed together. Within a single call, columns are AND-ed.

Usage

il_block_on(spec, ..., .where = NULL, .transform = NULL, .explode = NULL)

Arguments

spec

An il_spec object (piped in).

...

Columns for equality blocking (AND-ed within one call). Each entry is either:

• A bare column name, e.g. surname.

• A column ~ transform formula, e.g. first_name ~ il_substr(1, 3), which applies the transform to that column before the equality check. Mix bare names and formulas freely within one call.

.where

An optional raw SQL string for non-equality blocking conditions. Defaults to NULL.

.transform

An optional transform applied to every column that does not already have a formula transform. Can be a single function (e.g. il_soundex) or a named list of functions for per-column transforms. Formula transforms in ... take precedence over .transform.

.explode

An optional character vector of column names containing arrays (list columns) to unnest before blocking. Each array element becomes a separate row for the blocking join. Requires a DuckDB or PostgreSQL backend. Defaults to NULL.

Value

An updated copy of spec.

Examples

# Block on state OR first name (two calls = OR)
spec <- il_spec() |>
  il_block_on(state) |>
  il_block_on(first_name)

# Block where state AND year both match (one call = AND)
spec <- il_spec() |>
  il_block_on(state, year)

# Per-column substring blocking with formula syntax
spec <- il_spec() |>
  il_block_on(first_name ~ il_substr(1, 3), surname ~ il_substr(1, 4))

# Mix: substr on one column, plain match on another
spec <- il_spec() |>
  il_block_on(postcode_fake ~ il_substr(1, 3), dob)

# Same transform on all columns
spec <- il_spec() |>
  il_block_on(first_name, .transform = il_soundex)

# Explode array columns before blocking
spec <- il_spec() |>
  il_block_on(email, .explode = 'email')