Shiny 应用程序中的“match.arg(position) 错误：‘arg’必须为 NULL 或字符向量”

Question

I've been developing a Shiny app in a single app.R file (see below). I'm getting the "Error in match.arg(position) : 'arg' must be NULL or a character vector" error, but can't see why? I've looked at previous threads about this and they all seem to relate to issues with placement of the elements of the app (eg duplicate sidebarPanel etc), but I can't tell form them what I'm doing wrong. I've been developing this app, and it previous iterations the app has at least appeared, with the two selectInput's working. Any advice hugely appreciated. Apologies for my inelegant coding and layout as I've been trying to follow the formatting instructions, but it just makes it look even worse. Thinking of giving up completely, as I'm spending hours and getting absolutely nowhere.

Ian

#
# This is a Shiny web application. You can run the application by clicking
# the 'Run App' button above.
#

library(shiny)
library(shinydashboard) 
library(fingertipsR)
library(ggplot2)
library(viridis)
library(plotly)

#Import QOF indicators
setwd("/Users/ianbowns/Documents/R/ShinyFT")
dat <- readRDS("data")
my.df <- as.data.frame(dat)
#Defines year and age category choices
yearchoices <- unique(as.character(my.df$Timeperiod))
indicator <- unique(as.character(my.df$IndicatorName))
# Define UI for application that draws boxplot
ui <- fluidPage(

 # Application title
 titlePanel("FingerTips QOF Prevalences"),

 # Input for year and ages 
 sidebarLayout(
  sidebarPanel(
    selectInput(inputId = "year",
            label = "Choose a year:",
            choices = yearchoices,
            selected = "2015/16"),
    selectInput(inputId = "indicator",
            label = "Choose ages:",
            choices = indicators,
            selected = "All ages")),
  actionButton("goButton", "Refresh graph"),
  # Show a plot of the generated distribution
  mainPanel(
     plotlyOutput("bPlot")
  )
))


# Define server logic required to draw a histogram
server <- function(input, output) {

    inds <- my.df[which(IndicatorID == "input$indicator" & Sex == "Persons" 
          & Timeperiod == "input$year" & ParentCode != "E92000001"),]
# draw the boxplot
#                   input$goButton
        output$bPlot <- renderPlotly({
               plot_ly(data = inds, y = ~Value, color = inds$ParentName, 
type = "box", colors = viridis_pal(alpha = 1, begin = 0, end = 1, direction 
= -1, option = "D")(3), boxpoints = "all", jitter = 0.3, 
pointpos = -1.8) %>% 
               layout(title = "Dementia", titlefont = list(family = 
"Helvetica", size = 16), yaxis = list(title = "Prevalence (%)", titlefont = 
list(family = "Helvetica", size = 12)))})
}
# Run the application
shinyApp(ui = ui, server = server)

Answer 1

Since you havent provided any data to go with it, I will speculate that it doesnt work because you didnt wrap your data into a reactive expression. Try the server below:

# Define server logic required to draw a histogram
server <- function(input, output, session) {

  inds <- reactive({
    my.df[which(IndicatorID %in% input$indicator & Sex == "Persons" 
                & Timeperiod %in% input$year & ParentCode != "E92000001"),]
  })

  # draw the boxplot
  #                   input$goButton
  output$bPlot <- renderPlotly({
    plot_ly(data = inds(), y = ~Value, color = inds()$ParentName, 
            type = "box", colors = viridis_pal(alpha = 1, begin = 0, end = 1, direction 
                                               = -1, option = "D")(3), boxpoints = "all", jitter = 0.3, 
            pointpos = -1.8) %>% 
      layout(title = "Dementia", titlefont = list(family = 
                                                    "Helvetica", size = 16), yaxis = list(title = "Prevalence (%)", titlefont = 
                                                                                            list(family = "Helvetica", size = 12)))})
}
# Run the application
shinyApp(ui = ui, server = server)