We’ll start by making a new project to contain our app. We suggest making this in C:\work. From RStudio, choose File, New Project, New Directory, Shiny Web Application.
Choose a suitable name for the directory (e.g. “gapminder”). For “Creat project a subdirectory of:” we suggest using c:\work. At the end of the course, you can copy your project directory to your P drive. 01_defaultapp
When we create a new Shiny app we can create a single file (app.R), or as two separate files (ui.R and server.R). The latter format used to be the only method of defining an Shiny app, but can still be useful when building a more complicated app, as it allows us to separate the user interface (ui.R) from the server logic (server.R). As we will be building a relatively small app, we’ll use the single file approach.
When we create a new Shiny app in R Studio, it creates an example app that allows us to alter the number of bins in a histogram. This uses an example data-set that is provided with R of the waiting times for the eruption of the “Old Faithful” geyser.
We can run the app by pressing the “Run App” button in the tool-bar (or by pressing Ctrl+Shift+Enter). This will launch an browser window within R Studio where we can interact with our app.
There is a cheat sheet for Shiny included with R Studio. This can be accessed from the menu: Help, Cheatsheets, Web Applications with shiny.
The default app doesn’t use any additional libraries, functions or external data. Before going any further we’ll add these to the example app.
The working directory of your R session is probably your P:/ (this is displayed at the top of the console window). When you run the app, it runs in its own working directory (e.g. c:/work/gapminder). If you’re interactively running bits of your code you may find it helpful to set the working directory to your app’s directory. You can do this by typing setwd("c:/work/gapminder")
gapminder.rds and workshopFunctions.R files into your app directory.ggplot2 and dplyr libraries at the start of the appgapminder.rds into an object called gapminder using the readRDS() functionsource() the workshopFunctions.R file in the app to make the functions available to the appYou may wish to look at the codeExample.R file, which contains examples of loading libraries and functions