闪亮的R：具有“输入”数据选择的交互式切换输出

Question

I have a question about the data selection of interactive toggle shiny app. I would like to make the data selected from selectInput but the error say: Operation not allowed without an active reactive context. (You tried to do something that can only be done from inside a reactive expression or observer.)

Is there any way to make the data interactive with the input?

Thank you!

Here is my app:

app.r:

ui <- fluidPage(
fluidRow(
column(width = 6,
       selectInput("vsselection", "Choose a vs:", 
                   choices = names(table(data.frame(mtcars$vs))),selected=0),
       plotOutput("plot1", height = 350,
                  click = "plot1_click",
                  brush = brushOpts(
                    id = "plot1_brush"
                  )
       ),
       actionButton("exclude_toggle", "Toggle points"),
       actionButton("exclude_reset", "Reset")
  )
 )
)

server <- function(input, output) {
# For storing which rows have been excluded
vals <- reactiveValues(
keeprows = rep(TRUE, nrow(mtcars[which(mtcars$vs==input$vsselection),]))
)

output$plot1 <- renderPlot({
# Plot the kept and excluded points as two separate data sets
keep    <- mtcars[which(mtcars$vs==input$vsselection),][ vals$keeprows, ,  drop = FALSE]
exclude <- mtcars[which(mtcars$vs==input$vsselection),][!vals$keeprows, , drop = FALSE]

 ggplot(keep, aes(wt, mpg)) + geom_point() +
  geom_smooth(method = lm, fullrange = TRUE, color = "black") +
  geom_point(data = exclude, shape = 21, fill = NA, color = "black", alpha = 0.25) +
  coord_cartesian(xlim = c(1.5, 5.5), ylim = c(5,35))
 })

# Toggle points that are clicked
observeEvent(input$plot1_click, {
res <- nearPoints(mtcars[which(mtcars$vs==input$vsselection),],  input$plot1_click, allRows = TRUE)

vals$keeprows <- xor(vals$keeprows, res$selected_)
})

# Toggle points that are brushed, when button is clicked
observeEvent(input$exclude_toggle, {
res <- brushedPoints(mtcars[which(mtcars$vs==input$vsselection),],  input$plot1_brush, allRows = TRUE)

vals$keeprows <- xor(vals$keeprows, res$selected_)
})

# Reset all points
observeEvent(input$exclude_reset, {
vals$keeprows <- rep(TRUE,  nrow(mtcars[which(mtcars$vs==input$vsselection),]))
})

}

shinyApp(ui, server)

Answer 1

I guess the first thing you should to, is to change vals to vals <- reactive({...}) and then when referring to it, add parenthesis, eg vals()$keeprows . This should solve the reactivity problem.

Answer 2

Finally, I solved this issue by removing the interactive part from the object of reactiveValues() by keep the interactive part of Vals .

Note that values taken from the reactiveValues object are reactive, but the reactiveValues object itself is not.

Here is my app:

app.r:

ui <- fluidPage(
fluidRow(
column(width = 6,
       selectInput("vsselection", "Choose a vs:", 
                   choices =   names(table(data.frame(mtcars$vs))),selected=0),
       plotOutput("plot1", height = 350,
                  click = "plot1_click",
                  brush = brushOpts(
                    id = "plot1_brush"
                  )
       ),
       actionButton("exclude_toggle", "Toggle points"),
       actionButton("exclude_reset", "Reset")
  )
)
)

server <- function(input, output) {
# For storing which rows have been excluded
vals <- reactiveValues(
keeprows = rep(TRUE, nrow(mtcars))
)

output$plot1 <- renderPlot({
# Plot the kept and excluded points as two separate data sets
keep    <- mtcars[which(mtcars$vs==input$vsselection),][ vals$keeprows, ,   drop = FALSE]
exclude <- mtcars[which(mtcars$vs==input$vsselection),][!vals$keeprows, , drop = FALSE]

 ggplot(keep, aes(wt, mpg)) + geom_point(color = "blue") +
  geom_smooth(method = lm, fullrange = TRUE, color = "black") +
  geom_point(data = exclude, shape = 21, fill = NA, color = "black", alpha =  0.25) 
})

# Toggle points that are clicked
observeEvent(input$plot1_click, {
res <- nearPoints(mtcars[which(mtcars$vs==input$vsselection),],  input$plot1_click, allRows = TRUE)

vals$keeprows <- xor(vals$keeprows, res$selected_)
})

# Toggle points that are brushed, when button is clicked
observeEvent(input$exclude_toggle, {
res <- brushedPoints(mtcars[which(mtcars$vs==input$vsselection),],  input$plot1_brush, allRows = TRUE)

vals$keeprows <- xor(vals$keeprows, res$selected_)
})

# Reset all points
observeEvent(input$exclude_reset, {
vals$keeprows <- rep(TRUE,   nrow(mtcars[which(mtcars$vs==input$vsselection),]))
})

}