Model Evaluation

Holdout Split

Train and Test Rows

Model evaluation starts by separating rows used for fitting from rows saved for checking predictions.

Program

Play the script to move the holdout boundary and watch the train/test counts change.

holdout_split.R 
ids <- 1:6
test_start <- 
train_ids <- ids[ids < test_start]
test_ids <- ids[ids >= test_start]
label <- paste(length(train_ids), length(test_ids), sep = ":")
cat(label, "\n", sep = "")

ids <- 1:6
test_start <- 
train_ids <- ids[ids < test_start]
test_ids <- ids[ids >= test_start]
label <- paste(length(train_ids), length(test_ids), sep = ":")
cat(label, "\n", sep = "")

ids <- 1:6
test_start <- 
train_ids <- ids[ids < test_start]
test_ids <- ids[ids >= test_start]
label <- paste(length(train_ids), length(test_ids), sep = ":")
cat(label, "\n", sep = "")
holdout A holdout set is kept separate from rows used to fit a model.
logical index `ids < test_start` selects rows before the test boundary.
length `length(train_ids)` counts selected row identifiers.