Types of input

Building Dashboards with shinydashboard

Png Kee Seng

Researcher

Input functions

In the UI, users can provide inputs
- These are like instructions to the waiter
In a shinyApp, instructions are communicated through the server
This is done so by adding input functions to the UI
<type>input(<identifying label>, <displayed label>, ...)
- The first argument is an identifying label
- The second argument is a displayed label
- The other arguments are specific to the type of input

An example: sleep study

Imagine that we carried out a sleep study and collected data
What could be some inputs that a shinyApp user can give?

Graphic of a sleep study

¹ Image by storyset on Freepik

selectInput

A common input used is selectInput()
This creates a drop-down menu with many possible options
The third argument is a vector containing possible options
In this example, we have four possible options.
For now, let's keep the server empty
Let's render the shinyApp by running shinyApp()

ui <- fluidPage(
  titlePanel("Sleeping habits in America"), 
    selectInput("selectlabel", 
                "Select an option",

                choices = c("Option 1", "Option 2", 
                            "Option 3", "Option 4"))

server <- function(input, output, session) {
}

shinyApp(ui, server)

selectInput

selectInput with a single selection.

selectInput with multiple selections

We can also add another argument called multiple

ui <- fluidPage(
titlePanel("Sleeping habits in America"), 
  selectInput("selectlabel", 
              "Select an option",
              choices = c("Option 1", "Option 2", "Option 3", "Option 4"),
              multiple = TRUE))
server <- function(input, output, session) {
}
shinyApp(ui, server)

selectInput with multiple selections

textInput

There are two other important arguments
- value: the value that the textbox is pre-filled with
- placeholder: a preview of what the textbox should be filled with

ui <- fluidPage(
  titlePanel("Sleeping habits in America"), 
  textInput("textlabel", 
            "Tell me your name", 

            value = "Birdie",

            placeholder = "Don"))

server <- function(input, output, session) {
}
shinyApp(ui, server)

textInput

textInput demo

checkboxInput

This provides a single checkbox in the app
value: either TRUE or FALSE, to toggle the initial state of the checkbox
There is also a variation of checkboxInput, called checkboxGroupInput

ui <- fluidPage(
  titlePanel("Sleeping habits in America"), 
  checkboxInput("checkboxlabel",
                "65 years and over",

                value = FALSE))


server <- function(input, output, session) {
}

shinyApp(ui, server)

checkboxInput

checkboxInput demo

sliderInput

This produces a slider that allows the user to do one of two things
- Select a single numerical value from a range of numbers
- Select two numerical values from a range of numbers
For users to select a single value, we need to set min and max
The initial value is determined by value
Step size is determined by step

ui <- fluidPage(
  titlePanel("Sleeping habits in America"), 
  sliderInput("sliderlabel",
              "Average hours of sleep",

              min = 7.5,
              max = 11,

              value = 9,

              step = 0.02))

server <- function(input, output, session) {
}

shinyApp(ui, server)

sliderInput

sliderInput demo. User can select just one value.

sliderInput with ranges

The slider can be made two-sided if value is set as a length 2 vector

ui <- fluidPage(
  titlePanel("Sleeping habits in America"), 
  sliderInput("sliderlabel",
              "Average hours of sleep",
              min = 7.5,
              max = 11,

              value = c(8, 10),

              step = 0.02))
server <- function(input, output, session) {
}

shinyApp(ui, server)

sliderInput with ranges

slider with ranges

Let's practice!

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