Convert to a Classification Prediction

Source: R/as_prediction_classif.R

Convert object to a PredictionClassif.

as_prediction_classif(x, ...)

# S3 method for PredictionClassif
as_prediction_classif(x, ...)

# S3 method for data.frame
as_prediction_classif(x, ...)

Arguments

x

(any)
Object to convert.
...

(any)
Additional arguments.

Value

PredictionClassif.

Examples

# create a prediction object
task = tsk("penguins")
learner = lrn("classif.rpart", predict_type = "prob")
learner$train(task)
p = learner$predict(task)

# convert to a data.table
tab = as.data.table(p)

# convert back to a Prediction
as_prediction_classif(tab)

#> <PredictionClassif> for 344 observations:
#>     row_ids     truth  response prob.Adelie prob.Chinstrap prob.Gentoo
#>           1    Adelie    Adelie  0.96688742     0.03311258  0.00000000
#>           2    Adelie    Adelie  0.96688742     0.03311258  0.00000000
#>           3    Adelie    Adelie  0.96688742     0.03311258  0.00000000
#> ---                                                                   
#>         342 Chinstrap Chinstrap  0.06349206     0.92063492  0.01587302
#>         343 Chinstrap Chinstrap  0.28571429     0.71428571  0.00000000
#>         344 Chinstrap Chinstrap  0.06349206     0.92063492  0.01587302

# split data.table into a list of data.tables
tabs = split(tab, tab$truth)

# convert back to list of predictions
preds = lapply(tabs, as_prediction_classif)

# calculate performance in each group
sapply(preds, function(p) p$score())

#>    Adelie.classif.ce Chinstrap.classif.ce    Gentoo.classif.ce 
#>          0.039473684          0.073529412          0.008064516