broom (version 0.4.1)

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

"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()
}