```
# We train a random forest on the Boston dataset:
data("Boston", package = "MASS")
library("rpart")
rf <- rpart(medv ~ ., data = Boston)
mod <- Predictor$new(rf, data = Boston)
# Compute the accumulated local effects for the first feature
eff <- FeatureEffect$new(mod, feature = "rm", grid.size = 30)
eff$plot()
# Again, but this time with a partial dependence plot and ice curves
eff <- FeatureEffect$new(mod,
feature = "rm", method = "pdp+ice",
grid.size = 30
)
plot(eff)
# Since the result is a ggplot object, you can extend it:
library("ggplot2")
plot(eff) +
# Adds a title
ggtitle("Partial dependence") +
# Adds original predictions
geom_point(
data = Boston, aes(y = mod$predict(Boston)[[1]], x = rm),
color = "pink", size = 0.5
)
# If you want to do your own thing, just extract the data:
eff.dat <- eff$results
head(eff.dat)
# You can also use the object to "predict" the marginal values.
eff$predict(Boston[1:3, ])
# Instead of the entire data.frame, you can also use feature values:
eff$predict(c(5, 6, 7))
# You can reuse the pdp object for other features:
eff$set.feature("lstat")
plot(eff)
# Only plotting the aggregated partial dependence:
eff <- FeatureEffect$new(mod, feature = "crim", method = "pdp")
eff$plot()
# Only plotting the individual conditional expectation:
eff <- FeatureEffect$new(mod, feature = "crim", method = "ice")
eff$plot()
# Accumulated local effects and partial dependence plots support up to two
# features:
eff <- FeatureEffect$new(mod, feature = c("crim", "lstat"))
plot(eff)
# FeatureEffect plots also works with multiclass classification
rf <- rpart(Species ~ ., data = iris)
mod <- Predictor$new(rf, data = iris, type = "prob")
# For some models we have to specify additional arguments for the predict
# function
plot(FeatureEffect$new(mod, feature = "Petal.Width"))
# FeatureEffect plots support up to two features:
eff <- FeatureEffect$new(mod, feature = c("Sepal.Length", "Petal.Length"))
eff$plot()
# show where the actual data lies
eff$plot(show.data = TRUE)
# For multiclass classification models, you can choose to only show one class:
mod <- Predictor$new(rf, data = iris, type = "prob", class = 1)
plot(FeatureEffect$new(mod, feature = "Sepal.Length"))
```

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