adds shiny R example

examples/shiny-r/Dockerfile

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+FROM r-base
+COPY . .
+RUN Rscript install.R
+ENTRYPOINT ["Rscript", "startApp.R"]

examples/shiny-r/app.R

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+library(shiny)
+library(bslib)
+library(dplyr)
+library(ggplot2)
+library(ggExtra)
+
+penguins_csv <- "https://raw.githubusercontent.com/jcheng5/simplepenguins.R/main/penguins.csv"
+
+df <- readr::read_csv(penguins_csv)
+# Find subset of columns that are suitable for scatter plot
+df_num <- df |> select(where(is.numeric), -Year)
+
+ui <- page_sidebar(
+  sidebar = sidebar(
+    varSelectInput("xvar", "X variable", df_num, selected = "Bill Length (mm)"),
+    varSelectInput("yvar", "Y variable", df_num, selected = "Bill Depth (mm)"),
+    checkboxGroupInput(
+      "species", "Filter by species",
+      choices = unique(df$Species), 
+      selected = unique(df$Species)
+    ),
+    hr(), # Add a horizontal rule
+    checkboxInput("by_species", "Show species", TRUE),
+    checkboxInput("show_margins", "Show marginal plots", TRUE),
+    checkboxInput("smooth", "Add smoother"),
+  ),
+  plotOutput("scatter")
+)
+
+server <- function(input, output, session) {
+  subsetted <- reactive({
+    req(input$species)
+    df |> filter(Species %in% input$species)
+  })
+
+  output$scatter <- renderPlot({
+    p <- ggplot(subsetted(), aes(!!input$xvar, !!input$yvar)) + list(
+      theme(legend.position = "bottom"),
+      if (input$by_species) aes(color = Species),
+      geom_point(),
+      if (input$smooth) geom_smooth()
+    )
+
+    if (input$show_margins) {
+      margin_type <- if (input$by_species) "density" else "histogram"
+      p <- ggExtra::ggMarginal(p, type = margin_type, margins = "both",
+        size = 8, groupColour = input$by_species, groupFill = input$by_species)
+    }
+
+    p
+  }, res = 100)
+}
+
+shinyApp(ui, server)

examples/shiny-r/install.R

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+install.packages("shiny")
+install.packages("bslib")
+install.packages("dplyr")
+install.packages("ggplot2")
+install.packages("ggExtra")
+install.packages("readr")

examples/shiny-r/startApp.R

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+library(shiny)
+options(shiny.host = '0.0.0.0')
+options(shiny.port = 80)
+runApp('app.R')