Updating spatial polygon dataframe with shiny - r

Question

My shapefile has columns mean, median and sd and i want to draw a choropleth map in R Shiny. I have a sidebar that controls if tiles of map should display mean, median or sd. But I am not able to do it in Shiny. I tried using the reactive funtions but I keep getting the error below
Error: Polygon data not found; please provide addPolygons with data and/or lng/lat arguments
My code is below
library(shiny)
library(leaflet)
library(rgdal)
library(RColorBrewer)
val <- readOGR('exampleshapefile.shp')
mybins <- c(24,270,470,555,770,2000,Inf)
ui <- fluidPage(
sidebarLayout(
sidebarPanel(
radioButtons("stat", "Stat Type:",
c("Mean" = "mean",
"Median" = "q0_50",
"Standard Deviation" = "sd"
)
)
),
mainPanel("mainpanel",
leafletOutput("distSAM")
)
)
)
server <- function(input, output) {
###################### dist-wise
data <- eventReactive(input$stat,{
val#data$input$stat
})
pal <- reactive({
colorBin(palette="RdYlGn", domain = data(), na.color = "transparent", bins=mybins, reverse = TRUE)
})
labels <- reactive({
sprintf(
"<strong>%s<br/>%s</strong>%.1f",
val#data[["NAME_2"]], "SAM: ", data()
) %>% lapply(htmltools::HTML)
})
output$distSAM <- renderLeaflet({
df <- data()
pal <- pal()
lab <- labels()
leaflet() %>% addTiles() %>%
addPolygons(data = df,
fillColor = ~pal(mean),
weight = 2,
opacity = 1,
color = "white",
dashArray = "3",
fillOpacity = 0.7,
highlight = highlightOptions(
weight = 5,
color = "#666",
dashArray = "",
fillOpacity = 0.7,
bringToFront = TRUE),
label = lab,
labelOptions = labelOptions(
style = list("font-weight" = "normal", padding = "3px 8px"),
textsize = "15px",
direction = "auto")) %>%
addLegend(pal = pal, values = ~df$mean,
title = "SAM </br> Prevalence",
position = "bottomleft")
}
)
}
shinyApp(ui, server)

Answer 1

val#data$input$stat is not a valid data selection. Instead you can use:
selected_stat <- val[[input$stat]]