Shiny programming: Date range select for stock plot using Quandl and Shiny

This experiment will plot the Microsoft stock or the Google stock depending on user input. User can also select a date range.

The Shiny application will be called Experiment2. To set things up I will need to create 4 things

1. Create an Experiment2 folder.
2. Create a server.R script file in the Experiment2 folder.
3. Create a ui.R script file in the Experiment2 folder.
4. Create an Experiment2_App.R script file outside the Experiment1 folder.

The server.R script is

library(shiny)
library(Quandl)
library(ggplot2)

shinyServer(function(input, output) {
 
  # Place this variable here. It will be run only once each time a user visits the app.
  # This makes the output unique to a particular user
  stkList <- data.frame(name=c("Microsoft", "Google"),symbol=c("GOOG/NASDAQ_MSFT","GOOG/NASDAQ_GOOGL" ),stringsAsFactors = FALSE)
 
  output$text1 <- renderText({
    paste("You have selected ",input$var)
  })
 
  #renderPlot function is required to plot the graph
  output$distPlot <- renderPlot({
   
    # Use grep to find the Quandl data code name
    # Place the Quandl function inside the render* function otherwise it does not become part of the
    # reactive component
    stkPrice <- Quandl(stkList[grep(input$var,stkList[,1], ignore.case = TRUE),2],
                       api_key="xxxxxxxxxxxxxxx",
                       trim_start=input$daterange[1],
                       trim_end=input$daterange[2],
                       order="asc")
   
    #ggplot qplot function
    qplot(stkPrice$Date,stkPrice$Close,
          geom=c("line","point"),
          xlab="Time",
          ylab=paste(input$var, " stock price"))

})
 
})

The ui.R script is

library(shiny)

shinyUI(fluidPage(
  titlePanel("Stock plotter with dateRangeInput reactive programming"),
 
  sidebarLayout(
    sidebarPanel(
      helpText("Stock plot using Quandl and Shiny"),
     
      selectInput("var",
                  label = "Choose a Microsoft or Google",
                  choices = c("Microsoft", "Google"),
                  selected = "Microsoft"),
     
      #dateRangeInput to select the dates required for the plotting
      dateRangeInput("daterange", "Date range:",
                     start  = "01-Jan-2015",
                     end    = "31-Jan-2016",
                     min    = "01-Jan-2000",
                     max    = "01-Jan-2017",
                     format = "dd-M-yyyy",
                     separator = " - ")
     
      ),
   
    mainPanel(
      textOutput("text1"),
      br(),
      plotOutput("distPlot")
    )
  )
))

The Experiment2_app.R script is

library(shiny)
runApp("Experiment2")

The output is rendered here

https://andrnev.shinyapps.io/Experiment2/