broom (version 0.4.0)

auc_tidiers: Tidiers for objects from the AUC package

Description

Tidy "roc" objects from the "auc" package. This can be used to, for example, draw ROC curves in ggplot2.

Usage

## S3 method for class 'roc':
tidy(x, ...)

Arguments

x

an "roc" object

...

Additional arguments, not used

Value

• A data frame with three columns:
• cutoff
  The cutoff of the prediction scores used for classification
• tpr
  The resulting true positive rate at that cutoff
• fpr
  The resulting false positive rate at that cutoff
• If the labels had names, those are added as an "instance" column.

Examples

if (require("AUC", quietly = TRUE)) {
  data(churn)
  r <- roc(churn$predictions,churn$labels)

  td <- tidy(r)
  head(td)

  library(ggplot2)
  ggplot(td, aes(fpr, tpr)) +
    geom_line()

  # compare the ROC curves for two prediction algorithms
  library(dplyr)
  library(tidyr)

  rocs <- churn %>%
    tidyr::gather(algorithm, value, -labels) %>%
    group_by(algorithm) %>%
    do(tidy(roc(.$value, .$labels)))

  ggplot(rocs, aes(fpr, tpr, color = algorithm)) +
    geom_line()
}