prep_transform: Apply a preprocessing plan to new data

In dataprep: Fast, Efficient, and Versatile Data Preprocessing and Reshaping with 'C++', 'OpenMP' & 'SIMD'

Apply a preprocessing plan to new data

Description

Uses a preprocessing plan created by prep_fit to transform new data. All parameters (thresholds, statistics, etc.) are taken from the plan and are not re‑estimated, thus ensuring that the same preprocessing logic is applied consistently and without data leakage.

Usage

prep_transform(plan, newdata, verbose = FALSE)

Arguments

plan	A preprocessing plan object returned by prep_fit.
newdata	A data frame containing the new data (e.g., test set) to be transformed. It must contain the same columns as the original training data used to build the plan.
verbose	Logical; if TRUE, prints progress messages.

Details

The function iterates through the steps stored in plan and applies the corresponding operations using the saved parameters. For example, if the "outlier" step used group‑specific thresholds, those exact thresholds are applied to the new data grouped in the same way.

Value

A data frame after applying the preprocessing steps specified in plan. The output contains the same variables as the training data after preprocessing.

Examples

# Build plan
plan <- prep_fit(data[1:100, c(1, 4, 47:49)], cols = 3:5, group = 2)
# Transform new data
newdata <- data[101:200, c(1, 4, 47:49)]
cleaned <- prep_transform(plan, newdata)

dataprep documentation built on Oct. 1, 2026, 5:07 p.m.