mlr_pipeops_imputeoor {mlr3pipelines} | R Documentation |
Out of Range Imputation
Description
Impute factorial features by adding a new level ".MISSING"
.
Impute numerical features by constant values shifted below the minimum or above the maximum by
using min(x) - offset - multiplier * diff(range(x))
or
max(x) + offset + multiplier * diff(range(x))
.
This type of imputation is especially sensible in the context of tree-based methods, see also Ding & Simonoff (2010).
If a factor is missing during prediction, but not during training, this adds an unseen level
".MISSING"
, which would be a problem for most models. This is why it is recommended to use
po("fixfactors")
and
po("imputesample", affect_columns = selector_type(types = c("factor", "ordered")))
(or some other imputation method) after this imputation method, if missing values are expected during prediction
in factor columns that had no missing values during training.
Format
R6Class
object inheriting from PipeOpImpute
/PipeOp
.
Construction
PipeOpImputeOOR$new(id = "imputeoor", param_vals = list())
-
id
::character(1)
Identifier of resulting object, default"imputeoor"
. -
param_vals
:: namedlist
List of hyperparameter settings, overwriting the hyperparameter settings that would otherwise be set during construction. Defaultlist()
.
Input and Output Channels
Input and output channels are inherited from PipeOpImpute
.
The output is the input Task
with all affected features having missing values imputed as described above.
State
The $state
is a named list
with the $state
elements inherited from PipeOpImpute
.
The $state$model
contains either ".MISSING"
used for character
and factor
(also
ordered
) features or numeric(1)
indicating the constant value used for imputation of
integer
and numeric
features.
Parameters
The parameters are the parameters inherited from PipeOpImpute
, as well as:
-
min
::logical(1)
Shouldinteger
andnumeric
features be shifted below the minimum? Initialized to TRUE. If FALSE they are shifted above the maximum. See also the description above. -
offset
::numeric(1)
Numerical non-negative offset as used in the description above forinteger
andnumeric
features. Initialized to 1. -
multiplier
::numeric(1)
Numerical non-negative multiplier as used in the description above forinteger
andnumeric
features. Initialized to 1.
Internals
Adds an explicit new level()
to factor
and ordered
features, but not to character
features.
For integer
and numeric
features uses the min
, max
, diff
and range
functions.
integer
and numeric
features that are entirely NA
are imputed as 0
.
Fields
Only fields inherited from PipeOp
.
Methods
Only methods inherited from PipeOpImpute
/PipeOp
.
References
Ding Y, Simonoff JS (2010). “An Investigation of Missing Data Methods for Classification Trees Applied to Binary Response Data.” Journal of Machine Learning Research, 11(6), 131-170. https://jmlr.org/papers/v11/ding10a.html.
See Also
https://mlr-org.com/pipeops.html
Other PipeOps:
PipeOp
,
PipeOpEncodePL
,
PipeOpEnsemble
,
PipeOpImpute
,
PipeOpTargetTrafo
,
PipeOpTaskPreproc
,
PipeOpTaskPreprocSimple
,
mlr_pipeops
,
mlr_pipeops_adas
,
mlr_pipeops_blsmote
,
mlr_pipeops_boxcox
,
mlr_pipeops_branch
,
mlr_pipeops_chunk
,
mlr_pipeops_classbalancing
,
mlr_pipeops_classifavg
,
mlr_pipeops_classweights
,
mlr_pipeops_colapply
,
mlr_pipeops_collapsefactors
,
mlr_pipeops_colroles
,
mlr_pipeops_copy
,
mlr_pipeops_datefeatures
,
mlr_pipeops_decode
,
mlr_pipeops_encode
,
mlr_pipeops_encodeimpact
,
mlr_pipeops_encodelmer
,
mlr_pipeops_encodeplquantiles
,
mlr_pipeops_encodepltree
,
mlr_pipeops_featureunion
,
mlr_pipeops_filter
,
mlr_pipeops_fixfactors
,
mlr_pipeops_histbin
,
mlr_pipeops_ica
,
mlr_pipeops_imputeconstant
,
mlr_pipeops_imputehist
,
mlr_pipeops_imputelearner
,
mlr_pipeops_imputemean
,
mlr_pipeops_imputemedian
,
mlr_pipeops_imputemode
,
mlr_pipeops_imputesample
,
mlr_pipeops_kernelpca
,
mlr_pipeops_learner
,
mlr_pipeops_learner_pi_cvplus
,
mlr_pipeops_learner_quantiles
,
mlr_pipeops_missind
,
mlr_pipeops_modelmatrix
,
mlr_pipeops_multiplicityexply
,
mlr_pipeops_multiplicityimply
,
mlr_pipeops_mutate
,
mlr_pipeops_nearmiss
,
mlr_pipeops_nmf
,
mlr_pipeops_nop
,
mlr_pipeops_ovrsplit
,
mlr_pipeops_ovrunite
,
mlr_pipeops_pca
,
mlr_pipeops_proxy
,
mlr_pipeops_quantilebin
,
mlr_pipeops_randomprojection
,
mlr_pipeops_randomresponse
,
mlr_pipeops_regravg
,
mlr_pipeops_removeconstants
,
mlr_pipeops_renamecolumns
,
mlr_pipeops_replicate
,
mlr_pipeops_rowapply
,
mlr_pipeops_scale
,
mlr_pipeops_scalemaxabs
,
mlr_pipeops_scalerange
,
mlr_pipeops_select
,
mlr_pipeops_smote
,
mlr_pipeops_smotenc
,
mlr_pipeops_spatialsign
,
mlr_pipeops_subsample
,
mlr_pipeops_targetinvert
,
mlr_pipeops_targetmutate
,
mlr_pipeops_targettrafoscalerange
,
mlr_pipeops_textvectorizer
,
mlr_pipeops_threshold
,
mlr_pipeops_tomek
,
mlr_pipeops_tunethreshold
,
mlr_pipeops_unbranch
,
mlr_pipeops_updatetarget
,
mlr_pipeops_vtreat
,
mlr_pipeops_yeojohnson
Other Imputation PipeOps:
PipeOpImpute
,
mlr_pipeops_imputeconstant
,
mlr_pipeops_imputehist
,
mlr_pipeops_imputelearner
,
mlr_pipeops_imputemean
,
mlr_pipeops_imputemedian
,
mlr_pipeops_imputemode
,
mlr_pipeops_imputesample
Examples
library("mlr3")
set.seed(2409)
data = tsk("pima")$data()
data$y = factor(c(NA, sample(letters, size = 766, replace = TRUE), NA))
data$z = ordered(c(NA, sample(1:10, size = 767, replace = TRUE)))
task = TaskClassif$new("task", backend = data, target = "diabetes")
task$missings()
po = po("imputeoor")
new_task = po$train(list(task = task))[[1]]
new_task$missings()
new_task$data()
# recommended use when missing values are expected during prediction on
# factor columns that had no missing values during training
gr = po("imputeoor") %>>%
po("fixfactors") %>>%
po("imputesample", affect_columns = selector_type(types = c("factor", "ordered")))
t1 = as_task_classif(data.frame(l = as.ordered(letters[1:3]), t = letters[1:3]), target = "t")
t2 = as_task_classif(data.frame(l = as.ordered(c("a", NA, NA)), t = letters[1:3]), target = "t")
gr$train(t1)[[1]]$data()
# missing values during prediction are sampled randomly
gr$predict(t2)[[1]]$data()