sync_meta: Re-align metadata with a transformed data frame

In artoo: Lossless CDISC-Native Input and Output for Clinical Datasets

Re-align metadata with a transformed data frame

Description

Re-attach and reconcile a artoo_meta after a transformation that dropped or reshaped it: the metadata's columns are narrowed and reordered to the frame's current columns, the record count is refreshed, the keys are recomputed, and a column the metadata does not describe gets an entry synthesized from its class and attributes. The one-liner to run after a dplyr (or base) pipeline, before handing the frame to a ⁠write_*()⁠ codec.

Usage

sync_meta(x, meta = NULL)

Arguments

x	The transformed data frame. ⁠<data.frame>: required⁠.
meta	The metadata to reconcile against. ⁠<artoo_meta> | NULL⁠. NULL (default) uses the frame's own metadata_json attribute. Requirement: when the transform dropped the attribute (base [ subsetting does), capture get_meta() before the pipeline and pass it here; a bare frame with no meta aborts with artoo_error_input.

Details

Why it exists. Base row subsetting (x[i, ]) drops the frame's metadata_json attribute, and many tidyverse verbs rebuild the frame. sync_meta() takes the last-known metadata (the frame's own attribute when it survived, or an explicit meta) and makes it agree with the data again, so the round trip stays lossless without hand-editing.

Value

A ⁠<data.frame>⁠: x re-stamped with the reconciled artoo_meta. Hand it to any ⁠write_*()⁠ codec.

See Also

Read / attach: get_meta(), set_meta().

Produce conformed frames: apply_spec().

Examples

spec <- artoo_spec(cdisc_adam_datasets, cdisc_adam_variables, codelists = cdisc_codelists)

# ---- Example 1: re-attach after an attribute-dropping subset ----
#
# Base subsetting drops the metadata; capture it first, transform, then
# sync. The metadata narrows to the kept columns and the new row count.
adsl <- apply_spec(cdisc_adsl, spec, "ADSL", conformance = "off")
meta <- get_meta(adsl)
elderly <- adsl[adsl$AGE > 65, c("STUDYID", "USUBJID", "AGE")]
synced <- sync_meta(elderly, meta)
get_meta(synced)@dataset$records

# ---- Example 2: a derived column gains a synthesized entry ----
#
# A new column the metadata does not describe is profiled from its class,
# so the frame still writes losslessly.
adsl$AGEGR9 <- ifelse(adsl$AGE > 65, ">65", "<=65")
synced2 <- sync_meta(adsl)
get_meta(synced2)@columns$AGEGR9$dataType

artoo documentation built on July 23, 2026, 1:08 a.m.