The author of this solution confirmed that it was only designed to work with local Shiny apps, since it makes OS shell calls to display a directory dialog. This works fine on a local machine, but does not work if the app is deployed to a shinyapps server. I played with it a bit and I like it so far.I am building a shiny app that requires a user to select a folder on the local machine, which contains the files to be processed by the app. If you’re primarily interested in reactive dashboards have a look at shiny dashboard. As for many Rstudio/tidyverse tools there’s also a handy cheat sheet. The official shiny tutorial, from which this post was digested, contains a list of 11 example apps that demonstrate various use cases.Ĭheck out the pretty comprehensive shiny gallery for plenty of inspiration. In the code, the server function builds a list-like object output based on the user input: server The only difference is that parameters are passed from the input UI, and that none of the possible parameters should break your plots. This part is close to a typical R workflow, in that you build your plots or tables to communicate insights. Here is where all the computations happen that produce the data for our output elements based on the input parameters. Similar to the inputID above, the outputID connects UI elements to server computations.īesides the plotOutput function, there are other functions to produce tables, images, text, and more. We choose a plot because plots are awesome: mainPanel(plotOutput(outputId = "bars")) This object will change immediately when the user selects a different input (here via the sliders). The mainPanel typically contains the rendered reactive output.
The line breaks are there for aesthetic reasons, to make the height of the sidebar and main boxes roughly the same. Raw HTML needs to wrapped via the HTML() function (thanks stackoverflow!). Shiny tags like tag$p or tag$a are named after their HTML equivalents. At the end, there is always a call to the shinyApp function which renders the whole thing. The shiny code is structured into two main elements: (i) a user interface (UI) definition and layout, and (ii) the server-side computations producing the data for plots (or tables, or other output elements). Besides the libraries, I’m also including the url for this post as part of the preparation. Note, that shiny web apps on shinyapps.io apparently need explicit library calls and that my normal approach of using invisible(lapply()) led to some confusing errors before I figured it out. This is unrelated to shiny (other than loading it): library(shiny) Preparations: Before we get to the interesting parts, the first five lines define and load the packages the script needs. Given the functionality of this app, 56 lines is not too bad, is it? Let’s dissect the code element by element! It visualises the resulting total numbers of Heads vs Tails as a reactive bar plot. The app allows you to choose the number of coin flips as well as the probability for Heads using slider bars. Geom_label(aes(flips, n, label = n), size = 5) +Īll you need to do at this stage is to (have the required libraries installed and) copy/paste the code above into an active R session. Mutate(flips = if_else(flips = 1, "Heads", "Tails"))
I considered it fitting to base it on the classic coin flip experiment which results in either Heads or Tails: # preparations required libraries Only 56 lines (a good chunk of which are comments and styling) in hopefully readable formatting. All credit goes to them I’m just trying to boil it down to the essentials to get you started within minutes.īelow is the complete code for my first shiny app. The content is digested from the official shiny tutorial which is great and definitely worth checking out for more details. This post assumes some basic familiarity with R and the tidyverse, but no prior knowledge of shiny is required. As an absolute beginner, I want to document my learning journey in the hope that it will be useful for other first-time shiny users.
This week I decided to get started with the R shiny package for interactive web applications.
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