ERROR: object of type 'closure' is not subsettable... Any help on how to extract max, min values and their respective dates???

[Antony]

#stock prices app

#install.packages("shiny")
#install.packages("quantmod")

#load packages
library(shiny)
library(quantmod)
library(dplyr)

ret <- function(buy,sell){ #create a function that returns a return given buy price and sell price
  round(((sell-buy)/buy)*100,2)
}

ui <- fluidPage(# main argument for ui
  titlePanel("Stock Price Analysis"), #top panel
  
  sidebarLayout( #for side and main panel
    
    sidebarPanel(# creates side bar panel
      h3("Instructions"),
      h5("Please Read Carefully"),
      h6("Enjoy your trading"),
      helpText("Select a stock to examine.
                Select dates of interest for the graph and return calculation.
               Information will be collected from Yahoo Finance."), #generate help text
      textInput(inputId = "symb", label = "Ticker Symbol", "SPY"), #label symbol, defaul is SPY
      
      dateRangeInput("dates", #input ID for function that receives two dates and generates a vector across the range
                     "Date range to view",
                     start = "2013-01-01",
                     end = as.character(Sys.Date())),
      
      dateInput("dateBought", #input ID
                "Date stock is bought",
                value = "2015-01-02"),
      
      dateInput("dateSold", #input ID
                "Date stock is sold",
                value = "2015-01-10"),
    ), #close sidebarPanel
    
    mainPanel(#main panel
      img(src = "rstudio.png", height = 40, width = 100),##Includes the R studio image
      h6("minimum"),
      h2(htmlOutput("minprice")),
      h6("maximum"),
      h2(htmlOutput("maxprice")),
      
      textOutput("text"), #output Text
      plotOutput("plot") #output plot
    ) #close main panel
    
  ) #end sidebarLayout
  
) #end fluidPage



server <- function(input,output) {
  
  stockPrices <- reactive({
    getSymbols(input$symb, src = "yahoo",
               from = input$dates[1],
               to = input$dates[2],
               auto.assign = FALSE)
    
  })
  
  
  output$text <- renderText({
    buyPrice <-
      getSymbols(input$symb, src = "yahoo",
                 from = input$dateBought,
                 to = as.Date(input$dateBought)+5,
                 auto.assign = FALSE)
    
    sellPrice <-
      getSymbols(input$symb, src = "yahoo",
                 from = input$dateSold,
                 to = as.Date(input$dateSold)+5,
                 auto.assign = FALSE) 
    
    
    paste("Your return is",paste0(ret(as.numeric(buyPrice[1,1]),as.numeric(sellPrice[1,1])),"%"))
    
    })
  
  
  output$plot <- renderPlot({
    
    chartSeries(stockPrices(), theme = chartTheme("white"),
                type = "line", TA = NULL, name = paste(input$symb, "Prices"))
    
    output$minprice <- renderText(
      paste('Price : $', min(stockPrices[,2]), '<br>Date :', rownames(stockPrices)[which.min(stockPrices$Price)] )
    )
    output$maxprice <- renderText(
      paste('Price : $', max(stockPrices[,2]), '<br>Date :', rownames(stockPrices)[which.max(stockPrices$Price)] )
    )
    
  })
  
}

shinyApp(ui, server) #run app

[nirgrahamuk]

when you want the values from a reactive, you use parentheses ()

@Antony

min(stockPrices[,2])

 min(stockPrices()[,2])

[Antony]

Thank you for your reply.
Am getting the same error with parentheses()

[nirgrahamuk]

You didnt add paranthesis in all the places you need them.
i.e.

 output$minprice <- renderText(
      paste('Price : $', min(stockPrices()[,2]), '<br>Date :', rownames(stockPrices())[which.min(stockPrices()$Price)] )
    )
    output$maxprice <- renderText(
      paste('Price : $', max(stockPrices()[,2]), '<br>Date :', rownames(stockPrices())[which.max(stockPrices()$Price)] )
    )

[Antony]

I have been able to extract the max and min using the parentheses() as you have advised, but their respective dates are blank. Thank you.

[nirgrahamuk]

There are a few issues.
1). you dont have a Price column, i.e. you seem to assume its column2 in the min call but then that its named Price in the which.min call.
I've continued to assume its the 2nd column you want.
2) its not a classic data.frame with rownames situation, its a zoo time series data.frame, so it has an index.

    output$minprice <- renderText({  
      sp <- stockPrices()
      paste('Price : $', min(sp[,2]), '<br>Date :', 
            index(sp)[which.min(sp[,2])] )
})

[Antony]

Thank you for your help, it working