In NicolasJBM/writer: Functions and interfaces to support academic writing with R

#Load necessary packages
library(learnr)
library(tidyr)
library(dplyr)
library(checkr)

#Set global options for the exercises
knitr::opts_chunk$set(echo = FALSE)
tutorial_options(exercise.eval=TRUE)
knitr::opts_chunk$set(exercise.checker = checkr::checkr_tutor)

#Load data
faithful_data <- sample_n(faithful, 100)

#Run simulations

Topic 1 {data-progressive=FALSE}

Exercise {data-allow-skip=TRUE}

Here's a simple exercise with an empty code chunk provided for entering the answer.

Write the R code required to add two plus two Theory [@Ittner2007]:

Exercise with Code {data-allow-skip=TRUE}

Here's an exercise with some prepopulated code as well as exercise.lines = 5 to provide a bit more initial room to work.

Now write a function that adds any two numbers and then call it:

add <- function() {

}

Topic 2

Exercise with Hint

Here's an exercise where the chunk is pre-evaulated via the exercise.eval option (so the user can see the default output we'd like them to customize). We also add a "hint" to the correct solution via the chunk immediate below labeled print-limit-hint.

Modify the following code to limit the number of rows printed to 5:

mtcars

head(mtcars)

Exercise with solution

# Change the filter to select February rather than January
mtcars <- filter(mtcars, cyl == 6)

mtcars <- filter(mtcars, cyl == 8)

Quiz

You can include any number of single or multiple choice questions as a quiz. Use the question function to define a question and the quiz function for grouping multiple questions together.

Some questions to verify that you understand the purposes of various base and recommended R packages:

quiz(
  question("Which package contains functions for installing other R packages?",
    answer("base"),
    answer("tools"),
    answer("utils", correct = TRUE),
    answer("codetools"),
    allow_retry = TRUE
  ),
  question("Which of the R packages listed below are used to create plots?",
    answer("lattice", correct = TRUE),
    answer("tools"),
    answer("stats", message = "Sorry, but this is for statitics."),
    answer("grid", correct = TRUE),
    allow_retry = TRUE
  )
)

Exercise with a value check

Change the filter to select 8 cylinders instead of 6.

# Compute 2 + 2
4 + 4

# code to check exercise here
test_1 <- find_call("whatever + whatever",  
            message = "need to use addition (+)")
test_2 <- find_call("2 + whatever", 
            message = "first argument should be 2")
test_3 <- find_call("whatever + 2", 
            message = "second argument should be 2")
test_4 <- check_value(agrees(x == 4), 
            message = "the result should be 4")
USER_CODE %>% test_1 %>% test_2 %>% test_3 %>% final_ %>% test_4

Shiny prerendered

selectInput("n_breaks", label = "Number of bins:",
            choices = c(10, 20, 35, 50), selected = 20)

sliderInput("bw_adjust", label = "Bandwidth adjustment:",
            min = 0.2, max = 2, value = 1, step = 0.2)

plotOutput("eruptions")

output$eruptions <- renderPlot({
  hist(faithful_data$eruptions, probability = TRUE,
       breaks = as.numeric(input$n_breaks),
       xlab = "Duration (minutes)", main = "Geyser Eruption Duration")

  dens <- density(faithful_data$eruptions, adjust = input$bw_adjust)
  lines(dens, col = "blue")
})