In TuCai/podr: Common Functions for 'PHUSE' Open Data Repository

library(learnr)
knitr::opts_chunk$set(echo = FALSE)

Topic 1

Exercise

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:

Exercise with Code

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)

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")
  ),
  question("Which of the R packages listed below are used to create plots?",
    answer("lattice", correct = TRUE),
    answer("tools"),
    answer("stats"),
    answer("grid", correct = TRUE)
  )
)

Test to use a small R Shiny app to demonstrate this function.

# load libraries
# library(learnr)
library(shiny)
library(podr)
# set options/configuration
knitr::opts_chunk$set(echo = FALSE)

# load data
cc  <- getOption("podr_tables")
tbs <- as.list(sort(cc$table_name))

  uiOutput("tabTable")
  DT::dataTableOutput("DT3")

output$DT3 <- renderDataTable({
    tb <- input$tab;
    rr <- data.frame()
    if (is_empty(tb)) { return(datatable(rr)) }
    rr <- get_table_defs(tb) 
    datatable(rr)
  })
output$tabTable <- renderUI({
  cc  <- getOption("podr_tables")
  tbs <- as.list(sort(cc$table_name))
  selectInput("tab", "Table Name: ", multiple = FALSE, choices = tbs  , selected = input$tab)
})

library(shiny)
library(DT)
library(shinyjs)
library(shinyBS)
library(shinydashboard)

ui <- fluidPage(
  mainPanel(
    tabPanel("Table", uiOutput("tabTable"))
  )
)
server <- function(input, output, session) {
   get_tab_list <- reactive({
    cc <- getOption("podr_tables")
    as.list(sort(cc$table_name))
  })

 get_title <- reactive ({
    paste("Table Definition for", toupper(input$tab), sep = " ")
  })

  output$DT3 <- renderDataTable({
    tb <- input$tab;
    rr <- data.frame()
    if (is_empty(tb)) { return(datatable(rr)) }
    rr <- get_table_defs(tb) 
    datatable(rr)
  })

  output$tabTable <- renderUI({
    cc <- getOption("podr_tables")
    libs <- as.list(unique(sort(cc$libname)))
    tabPanel("Show"
             , div(id = "form"
                   , selectInput("tab", "Table Name: ", multiple = FALSE
                                 , choices = get_tab_list()  , selected = input$tab)
             )
             , hr()
             , h1(get_title())
             , DT::dataTableOutput("DT3")
    )
  })
}
  shinyApp(ui, server)

TuCai/podr documentation built on June 8, 2021, 5:37 a.m.