In jayemerson/ShinyHelper: Making Shiny Application Creation Easier (maybe)

This Presentation

• Official resources
• Toy example (stand-alone)
• Toy example (via ShinyHelper) embedded in this presentation (method 1)
• Slightly expanded example embedded in this presentation (method 2)

Where To Go (official resources)

Googling can reveal some older tutorials and documentation. None of this is my work; my stuff is of secondary importance in the grand scheme of things and will be referenced later, separately. The newest and greatest official resources, as far as I know:

• Tutorial, documentation, examples: http://shiny.rstudio.com
• Source code (and see inst/examples/ for some good example): https://github.com/rstudio/shiny
• Serious deployment (Alpha version): https://www.shinyapps.io

01_hello/ folder contents

This example is included with the shiny package in the inst/examples directory along with other goodies. We'll look at it, then we'll run it.

Jays-MacBook-Pro:Shiny_master jay$ ls 01_hello/

server.R  ui.R

The following code is mildly edited to display well in the presentation.

01_hello/ui.R

library(shiny)

shinyUI(fluidPage(
  titlePanel("Hello Shiny!"),
  sidebarLayout(
    sidebarPanel(
      sliderInput("bins", "Number of bins:",
                  min = 1, max = 50, value = 30)
    ),
    mainPanel(
      plotOutput("distPlot")
    )
  )
))

01_hello/server.R

library(shiny)

# Define server logic required to draw a histogram
shinyServer(function(input, output) {

  output$distPlot <- renderPlot({
    x    <- faithful[, 2]  # Old Faithful Geyser data
    bins <- seq(min(x), max(x), length.out = input$bins + 1)

    hist(x, breaks = bins, col = 'darkgray', border = 'white')
  })

})

Running 01_hello in browser

Jays-MacBook-Pro:Shiny_master jay$ ls

01_hello  Intro2Shiny.Rmd

Jays-MacBook-Pro:Shiny_master jay$ ls 01_hello/

server.R  ui.R

Jays-MacBook-Pro:Shiny_master jay$ R

  < snip -- I'm still apparently using R 3.1.1 >

> library(shiny)
> runApp("01_hello/")

Listening on http://127.0.0.1:7934
^C
>

unlink("SH_hello/", recursive=TRUE)

ShinyHelper:

Author simple Shiny apps with wrapper functions provided by ShinyHelper.

If you just want to build an occasional Shiny app, you probably don't need this. But if it becomes a regular thing, ShinyHelper lets you write an app using R code (rather than writing the app itself). Contributions would be welcome (providing new wrappers for more advanced Shiny features).

https://github.com/jayemerson/ShinyHelper

Buyer beware, no warranties, etc...

01_hello via ShinyHelper

require(devtools)
install_github('ShinyHelper', 'jayemerson')

library(ShinyHelper)

shinySkeleton("SH_hello")
headerPanelAdd("01_hello via ShinyHelper")
sliderInputAdd("bins", "Number of bins:",
               min = 1, max = 50, value = 30)
plotOutputAdd("distplot", plotcode =
'
  x    <- faithful[, 2]  # Old Faithful Geyser data
  bins <- seq(min(x), max(x), length.out = input$bins + 1)
  hist(x, breaks = bins, col = "darkgray", border = "white")
')
createApp("SH_hello", overwrite=TRUE)
# runApp("SH_hello") # We'll do something else...

Embedding SH_hello in this presentation

You can simply point your presentation to the folder containing your Shiny app. In this example, the following code goes into a simple code chunk on the next slide that looks like this (but with echo=FALSE as a code chunk option):

shinyAppDir(
  "SH_hello", options=list(width="100%", height=700)
)

SH_hello

shinyAppDir(
  "SH_hello", options=list(width="100%", height=700)
)

Embedding the Shiny app code inline

The example on the next pages comes from the default page template for a Shiny R Markdown presentation. See also:

http://rmarkdown.rstudio.com/authoring_shiny.html

Note that this approach doesn't use (require?) the "packaging" of inputPanel() and renderPlot() inside formal shinyServer() and shinyUI infrastructure. There is no formal directory containing the app, as with previous examples.

Embedded code for interactive plot

inputPanel(
  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)
)

renderPlot({
  hist(faithful$eruptions, probability = TRUE,
       breaks = as.numeric(input$n_breaks),
       xlab = "Duration (minutes)",
       main = "Geyser eruption duration")

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

Slide with Interactive Plot

inputPanel(
  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)
)

renderPlot({
  hist(faithful$eruptions, probability = TRUE,
       breaks = as.numeric(input$n_breaks),
       xlab = "Duration (minutes)",
       main = "Geyser eruption duration")

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

jayemerson/ShinyHelper documentation built on May 18, 2019, 5:57 p.m.