问题描述
在此处使用lmr3verse
软件包。假设我对用于训练Learner
的训练集进行了以下预处理:
preprocess <- po("scale",param_vals = list(center = TRUE,scale = TRUE)) %>>%
po("encode",param_vals = list(method = "one-hot"))
我想使用命令pred
来预测数据帧(包含原始变量)predict(Learner,newdata = pred,predict_type="prob")
中包含的新观测值的标签。由于Learner
经过集中,缩放和一键编码的变量训练,因此无法使用。
为了进行预测,如何将训练集上使用的相同预处理应用于新数据(仅功能而不是响应)?
解决方法
我不确定100%,但是您似乎可以将新数据提供给新任务并将其提供给predict
。 This page shows an example of combining mlr_pipeops
and learner
objects.
library(dplyr)
library(mlr3verse)
df_iris <- iris
df_iris$Petal.Width = df_iris$Petal.Width %>% cut( breaks = c(0,0.5,1,1.5,2,Inf))
task = TaskClassif$new(id = "my_iris",backend = df_iris,target = "Species")
train_set = sample(task$nrow,0.8 * task$nrow)
test_set = setdiff(seq_len(task$nrow),train_set)
task_train = TaskClassif$new(id = "my_iris",backend = df_iris[train_set,],# use train_set
target = "Species")
graph = po("scale",param_vals = list(center = TRUE,scale = TRUE)) %>>%
po("encode",param_vals = list(method = "one-hot")) %>>%
mlr_pipeops$get("learner",learner = mlr_learners$get("classif.rpart"))
graph$train(task_train)
graph$pipeops$encode$state$outtasklayout # inspect model input types
graph$pipeops$classif.rpart$predict_type = "prob"
task_test = TaskClassif$new(id = "my_iris_test",backend = df_iris[test_set,# use test_set
target = "Species")
pred = graph$predict(task_test)
pred$classif.rpart.output$prob
# when you don't have a target variable,just make up one
df_test2 <- df_iris[test_set,]
df_test2$Species = sample(df_iris$Species,length(test_set)) # made-up target
task_test2 = TaskClassif$new(id = "my_iris_test",backend = df_test2,# use test_set
target = "Species")
pred2= graph$predict(task_test2)
pred2$classif.rpart.output$prob
,
如@missuse所建议,通过使用(1),[1],[2],(2),[3],[4],(3),[5],[6],(4),[7],[8],...
然后使用graph <- preprocess %>>% Learner
命令,我可以使用原始graph_learner <- GraphLearner$new(graph)
来预测--- predict(TunedLearner,newdata = pred,predict_type="prob")
-。 >