step_lincomb()
creates a specification of a recipe step that will
potentially remove numeric variables that have exact linear combinations
between them.
step_lincomb(
recipe,
...,
role = NA,
trained = FALSE,
max_steps = 5,
removals = NULL,
skip = FALSE,
id = rand_id("lincomb")
)
A recipe object. The step will be added to the sequence of operations for this recipe.
One or more selector functions to choose variables
for this step. See selections()
for more details.
Not used by this step since no new variables are created.
A logical to indicate if the quantities for preprocessing have been estimated.
The number of times to apply the algorithm.
A character string that contains the names of
columns that should be removed. These values are not determined
until prep()
is called.
A logical. Should the step be skipped when the
recipe is baked by bake()
? While all operations are baked
when prep()
is run, some operations may not be able to be
conducted on new data (e.g. processing the outcome variable(s)).
Care should be taken when using skip = TRUE
as it may affect
the computations for subsequent operations.
A character string that is unique to this step to identify it.
An updated version of recipe
with the new step added to the
sequence of any existing operations.
This step can potentially remove columns from the data set. This may cause issues for subsequent steps in your recipe if the missing columns are specifically referenced by name. To avoid this, see the advice in the Tips for saving recipes and filtering columns section of selections.
This step finds exact linear combinations between two
or more variables and recommends which column(s) should be
removed to resolve the issue. This algorithm may need to be
applied multiple times (as defined by max_steps
).
When you tidy()
this step, a tibble is returned with
columns terms
and id
:
character, the selectors or variables selected
character, id of this step
The underlying operation does not allow for case weights.
Other variable filter steps:
step_corr()
,
step_filter_missing()
,
step_nzv()
,
step_rm()
,
step_select()
,
step_zv()
data(biomass, package = "modeldata")
biomass$new_1 <- with(
biomass,
.1 * carbon - .2 * hydrogen + .6 * sulfur
)
biomass$new_2 <- with(
biomass,
.5 * carbon - .2 * oxygen + .6 * nitrogen
)
biomass_tr <- biomass[biomass$dataset == "Training", ]
biomass_te <- biomass[biomass$dataset == "Testing", ]
rec <- recipe(HHV ~ carbon + hydrogen + oxygen + nitrogen +
sulfur + new_1 + new_2,
data = biomass_tr
)
lincomb_filter <- rec %>%
step_lincomb(all_numeric_predictors())
lincomb_filter_trained <- prep(lincomb_filter, training = biomass_tr)
lincomb_filter_trained
#>
#> ── Recipe ──────────────────────────────────────────────────────────────────────
#>
#> ── Inputs
#> Number of variables by role
#> outcome: 1
#> predictor: 7
#>
#> ── Training information
#> Training data contained 456 data points and no incomplete rows.
#>
#> ── Operations
#> • Linear combination filter removed: new_1 new_2 | Trained
tidy(lincomb_filter, number = 1)
#> # A tibble: 1 × 2
#> terms id
#> <chr> <chr>
#> 1 all_numeric_predictors() lincomb_IeIAm
tidy(lincomb_filter_trained, number = 1)
#> # A tibble: 2 × 2
#> terms id
#> <chr> <chr>
#> 1 new_1 lincomb_IeIAm
#> 2 new_2 lincomb_IeIAm