Preprocessing Tools to Create Design Matrices

An extensible framework to create and preprocess design matrices. Recipes consist of one or more data manipulation and analysis "steps". Statistical parameters for the steps can be estimated from an initial data set and then applied to other data sets. The resulting design matrices can then be used as inputs into statistical or machine learning models.


recipes 0.1.2

General Changes:

  • Edwin Thoen suggested adding validation checks for certain data characteristics. This fed into the existing notion of expanding recipes beyond steps (see the non-step steps project). A new set of operations, called checks, can now be used. These should throw an informative error when the check conditions are not met and return the existing data otherwise.

  • Steps now have a skip option that will not apply preprocessing when bake is used. See the article on skipping steps for more information.

New Operations:

  • check_missing will validate that none of the specified variables contain missing data.
  • step_num2factor can be used to convert numeric data (especially integers) to factors.
  • step_novel adds a new factor level to nominal variables that will be used when new data contain a level that did not exist when the recipe was prepared.
  • step_profile can be used to generate design matrix grids for prediction profile plots of additive models where one variable is varied over a grid and all of the others are fixed at a single value.
  • step_downsample and step_upsample can be used to change the number of rows in the data based on the frequency distributions of a factor variable in the training set. By default, this operation is only applied to the training set; bake ignores this operation.

Other Changes:

  • step_spatialsign now has the option of removing missing data prior to computing the norm.

recipes 0.1.1

  • The default selectors for bake was changed from all_predictors() to everything().
  • The verbose option for prep is now defaulted to FALSE
  • A bug in step_dummy was fixed that makes sure that the correct binary variables are generated despite the levels or values of the incoming factor. Also, step_dummy now requires factor inputs.
  • step_dummy also has a new default naming function that works better for factors. However, there is an extra argument (ordinal) now to the functions that can be passed to step_dummy.
  • step_interact now allows for selectors (e.g. all_predictors() or starts_with("prefix") to be used in the interaction formula.
  • step_YeoJohnson gained an na.rm option.
  • dplyr::one_of was added to the list of selectors.
  • step_bs adds B-spline basis functions.
  • step_unorder converts ordered factors to unordered factors.
  • step_count counts the number of instances that a pattern exists in a string.
  • step_string2factor and step_factor2string can be used to move between encodings.
  • step_lowerimpute is for numeric data where the values cannot be measured below a specific value. For these cases, random uniform values are used for the truncated values.
  • A step to remove simple zero-variance variables was added (step_zv).
  • A series of tidy methods were added for recipes and many (but not all) steps.
  • In bake.recipe, the argument newdata is now without a default.
  • bake and juice can now save the final processed data set in sparse format. Note that, as the steps are processed, a non-sparse data frame is used to store the results.
  • A formula method was added for recipes to get a formula with the outcome(s) and predictors based on the trained recipe.

recipes 0.1.0

First CRAN release.


  • Two of the main functions changed names. learn has become prepare and process has become bake


New steps:

  • step_lincomb removes variables involved in linear combinations to resolve them.
  • A step for converting binary variables to factors (step_bin2factor)
  • step_regex applies a regular expression to a character or factor vector to create dummy variables.

Other changes:

  • step_dummy and step_interact do a better job of respecting missing values in the data set.


  • The class system for recipe objects was changed so that pipes can be used to create the recipe with a formula.
  • process.recipe lost the role argument in factor of a general set of selectors. If no selector is used, all the predictors are returned.
  • Two steps for simple imputation using the mean or mode were added.

Reference manual

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0.1.2 by Max Kuhn, a month ago

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Browse source code at

Authors: Max Kuhn [aut, cre], Hadley Wickham [aut], RStudio [cph]

Documentation:   PDF Manual  

GPL-2 license

Imports tibble, stats, ipred, dimRed, lubridate, timeDate, ddalpha, purrr, rlang, gower, RcppRoll, tidyselect, magrittr, Matrix

Depends on dplyr, broom

Suggests testthat, rpart, kernlab, fastICA, RANN, igraph, knitr, caret, ggplot2, rmarkdown, covr

Imported by caret, formulize, olsrr, rsample.

Suggested by C50.

See at CRAN