R Notebook

Input and Output in R

** from the console

va = readline(prompt = 'Give your favorite integer: ');
vaInt <- as.integer(va) # va is a string
print(vaInt)
va2 = readline(prompt = 'Favorite color = ');
print(va2) # already is a string

** To input several things, you can use scan()

print('Give  us some characters:')

[1] "Give  us some characters:"

x <- scan(what = character()) # means we will input a character - or several
r
r
r
y
u
i6

Read 6 items

print('Give  us some text:')

[1] "Give  us some text:"

y <- scan(what = " ") # means you are inputting a string - or several
hubba
bubba
hello

Read 3 items

# the user will hit enter/return after each thing, then enter/return twice to keep going
print(x)

[1] "r"  "r"  "r"  "y"  "u"  "i6"

print(y)

[1] "hubba" "bubba" "hello"

# to add text from a file
s = scan("fileString.txt", what = " ") # pulls text out of the file

Making GUIs with R

Have to install the “Shiny” Package

library(shiny)

Registered S3 methods overwritten by 'htmltools':
  method               from         
  print.html           tools:rstudio
  print.shiny.tag      tools:rstudio
  print.shiny.tag.list tools:rstudio

Then – need to make two things - ui(user interface) + server function

Here is an example (modified example from shiny.rstudio.com or something like that)

# Define UI for app that draws a histogram ----
ui <- fluidPage(

  # App title ----
  titlePanel("Example of Shiny"),

  # Sidebar layout with input and output definitions ----
  sidebarLayout(

    # Sidebar panel for inputs ----
    sidebarPanel(
      #Put widgets here
      #Textbox input to change title of histogram
      textInput("titleHist", "Give title that you want", "Type here"),
      #first slot is the name of the string variable
      # second slot is the prompt
      # third slot is the text written in the textbox
      # Input: Slider for the number of bins ----
      sliderInput(inputId = "bins",
                  label = "Number of bins:",
                  min = 1,
                  max = 50,
                  value = 30) # the user will move the slider around

    ),

    # Main panel for displaying outputs ----
    mainPanel(
      # Put other widgets here
      # Output: Histogram ----
      plotOutput(outputId = "distPlot") #This is where the plot will be placed

    )
  )
)

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

  # Histogram of the Old Faithful Geyser Data ----
  # with requested number of bins
  # This expression that generates a histogram is wrapped in a call
  # to renderPlot to indicate that:
  #
  # 1. It is "reactive" and therefore should be automatically
  #    re-executed when inputs (input$bins) change
  # 2. Its output type is a plot
  #y <- renderText({input$titleHist})
  output$distPlot <- renderPlot({

    x    <- faithful$waiting #faithful is the dataframe
    bins <- seq(min(x), max(x), length.out = input$bins + 1)

    hist(x, breaks = bins, col = "#4D1979", border = "white",
         xlab = "Waiting time to next eruption (in mins)",
         main = input$titleHist)

    })

}

# Create Shiny app ---
shinyApp(ui = ui, server = server)

Listening on http://127.0.0.1:6117

More information https://shiny.rstudio.com/tutorial/written-tutorial/lesson1/