#RMARKDOWN PRINT VARIABLE CODE#
They also define reactive contexts and have the added benefit of defining their output - presumably your code has an output eventually, so you could just put all your code inside the renderX function that makes the kind of output you're looking for, and then it will all be in a reactive context without having to worry about creating your own contexts and what you assign them to and whatnot. The shiny package also provides some specific cases of reactive contexts and they're what you probably want to use most of the time - they're the renderX functions like renderDataTable, renderPlot and renderText. Usually you don't need to use it when you're making simple applications.
Reactive is a very general case of reactive contexts though. So when you put your input$variable inside reactive, you're creating a reactive context - it's a function that will return whatever value it had at the start, except if one of its inputs gets changed then it will re-run the code to calculate a new value. "Reactive" just means "is listening for changes and will run some code when those things change". The way you do this is with a reactive context.
#RMARKDOWN PRINT VARIABLE UPDATE#
The first thing you have to understand is that when you have some kind of input mechanism on the page, like a slider or a text box, you need to have a way to say to the server part of your application, "hey, this thing just changed, so go update the app". So, what is one, why is it important, and how do you get one? The error message says that you don't have one, and that's causing a problem. The important piece of context that is missing from that answer is what exactly an "active-reactive context" is. u/loyalservantofbrd gave you part of the answer - things you define with reactive are functions and must be called to get their most recent value. So how am I supposed to actually get the value of current_value into a useable form?
When I try to turn current_value into a numeric object, I get an error:Ĭannot coerce type 'closure' into type 'double'. When I ask what the class of current_value is, class(current_value) returns "reactiveExpr" "reactive". So how do I pass my interactively-inputted numbers to this printing-out code chunk? I expect the solution to be a trivial one but my google searching isn't going well.Ĭurrent_value <- reactive(input$variable)Īnd when I then just repeat 'current_value' on its own to output its value, it gives me the correct number when the document loads - but I still can't do anything with it. (You tried to do something that can only be done from isinde a reactive expression or observer.) Operation not allowed without an active-reactive context. When I attempt this via print(paste(.)) I get an error: For now I'd just like to print those numbers using a later code chunk. However, I then want to add a chunk where I use the numbers chosen. This much works fine, I hit 'run' and a working document appears where I can select the desired numbers from drop-down lists as intended. I have a code chunk where I call inputPanel(), in which have added a few calls to selectInput().
I'm trying to make an Rmd file for a shiny HTML document, my first ever attempt.
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