👀 Views: 2 💬 Answers: 1 📅 Created: 2025-06-11

r ggplot2 shiny R

I'm confused about I'm trying to create a series of dynamic faceted plots using `ggplot2` where the facet variable is determined by user input... However, I'm working with an scenario where the facets are not displayed correctly, and I get the following behavior: `behavior: Unknown variables: 'input$facet_var'`. I've tried using `aes_string()` and `facet_wrap()` with string interpolation, but the plots still don't render as expected. Here’s a simplified version of what I’ve been working on: ```r library(ggplot2) library(shiny) ui <- fluidPage( selectInput('facet_var', 'Select a variable to facet by:', choices = c('mpg', 'cyl')), plotOutput('plot') ) server <- function(input, output) { output$plot <- renderPlot({ ggplot(mtcars, aes(x = wt, y = hp)) + geom_point() + facet_wrap(as.formula(paste('~', input$facet_var))) }) } shinyApp(ui, server) ``` I've ensured that `input$facet_var` corresponds to a valid column in the `mtcars` dataset, but it still doesn't work. What am I missing here? Is there a better way to handle dynamic facets in `ggplot2` with Shiny? Any insights would be greatly appreciated! What are your experiences with this?