Shiny nearPoints() with slider input - r

Question

I was wondering if I can get rows data using nearPoints() from an interactive graph with slider input. My app.R file looks like:
library('shiny')
library('ggplot2')
dt <-read.csv('file.csv')
ui <- fluidPage(
plotOutput("plot1", height = 550, click = "plot1_click"),
fluidRow(
column(3,
sliderInput("Obs", "Number of Books", min = 1, max = nrow(up), value = 50)
),
column(3, offset = 3,
h4("Legends"),
verbatimTextOutput("selected")
)
)
)
server <- function(input, output) {
mydata <- reactive({
dt[1:as.numeric(input$Obs),]
})
output$plot1 <- renderPlot({
test <- mydata()
ggplot(data = test, aes(x = test[,2], y = test[,1])) + geom_point()
})
output$selected <- renderPrint({
file <- mydata()
nearPoints(file, input$plot1_click, threshold = 10, maxpoints = 1,
addDist = FALSE)
})
}
shinyApp(ui = ui, server = server)
Shiny nearPoints() is working perfectly without this slider input. When I used slider input, I can't get the row data until max. Is there any approach to work with the slider input? Any help is appreciated.

Answer 1

The following code works for me. It seems nearPoints is not able to tell which columns of your dataset are displayed because of the aes(x = test[,2], y = test[,1]) statement. Another possible fix sould be to set the parameters xvar and yvar in nearPoints.
library('shiny')
library('ggplot2')
dt <-mtcars
ui <- fluidPage(
plotOutput("plot1", height = 550, click = "plot1_click"),
fluidRow(
column(3,
sliderInput("Obs", "Number of Cars", min = 1, max = nrow(dt), value = 50)
),
column(3, offset = 3,
h4("Legends"),
verbatimTextOutput("selected")
)
)
)
server <- function(input, output) {
mydata <- reactive({
dt[1:as.numeric(input$Obs),]
})
output$plot1 <- renderPlot({
test <- mydata()
ggplot(data = test, aes(mpg, wt)) + geom_point()
})
output$selected <- renderPrint({
file <- mydata()
nearPoints(file, input$plot1_click, threshold = 100, maxpoints = 1,
addDist = FALSE)
})
}
shinyApp(ui = ui, server = server)
Quick note: Please try to make the code in your question reproducible by using one of the default datasets in R. You can get a list of all available datasets by calling data().