## ----setup, include = FALSE---------------------------------------------------
knitr::opts_chunk$set(
  collapse = TRUE,
  comment = "#>"
)

## ----pkgs, message = FALSE----------------------------------------------------
library(yardstick)
library(dplyr)

data("hpc_cv")

## ----hpc-cv-------------------------------------------------------------------
tibble(hpc_cv)

## ----hpc-modify---------------------------------------------------------------
set.seed(1)

hpc <-
  tibble(hpc_cv) %>%
  mutate(batch = sample(c("a", "b"), nrow(.), replace = TRUE)) %>%
  select(-c(VF, F, M, L))

hpc

## ----acc-1--------------------------------------------------------------------
hpc %>% 
  filter(Resample == "Fold01") %>%
  accuracy(obs, pred)

## ----hpc-cv-2-----------------------------------------------------------------
hpc %>% 
  group_by(Resample) %>%
  accuracy(obs, pred)

## ----res-1--------------------------------------------------------------------
hpc %>% 
  filter(Resample == "Fold01")

## ----acc-by-group-------------------------------------------------------------
acc_by_group <- 
  hpc %>% 
  filter(Resample == "Fold01") %>%
  group_by(batch) %>%
  accuracy(obs, pred)

acc_by_group

## ----diff-acc-----------------------------------------------------------------
diff(c(acc_by_group$.estimate[2], acc_by_group$.estimate[1]))

## -----------------------------------------------------------------------------
accuracy_diff <-
  new_groupwise_metric(
    fn = accuracy,
    name = "accuracy_diff",
    aggregate = function(acc_by_group) {
      diff(c(acc_by_group$.estimate[2], acc_by_group$.estimate[1]))
    }
  )

## ----acc-diff-class-----------------------------------------------------------
class(accuracy_diff)

## ----acc-diff-by--------------------------------------------------------------
accuracy_diff_by_batch <- accuracy_diff(batch)

## ----metric-classes-----------------------------------------------------------
class(accuracy)

class(accuracy_diff_by_batch)

## ----ex-acc-diff-by-batch-----------------------------------------------------
hpc %>% 
  filter(Resample == "Fold01") %>%
  accuracy_diff_by_batch(obs, pred)

## ----ex-acc-diff-by-batch-ms--------------------------------------------------
acc_ms <- metric_set(accuracy, accuracy_diff_by_batch)

hpc %>% 
  filter(Resample == "Fold01") %>%
  acc_ms(truth = obs, estimate = pred)

## ----ex-acc-diff-by-batch-2---------------------------------------------------
hpc %>% 
  group_by(Resample) %>%
  accuracy_diff_by_batch(obs, pred)