'closure' is not subsettable error in r shiny

Question

[Sude]

library(shiny)
library(tidyverse)
library(ISLR)
library(glmnet)
library(dplyr)
library(tidyr)
metadata <- readRDS("merging2.rds")
ui <- fluidPage( titlePanel("BLCA-GENE EXPRESSION"),

                 sidebarPanel(
                   selectInput(
                     inputId = "gene",
                     label = "Please choose a gene",
                     choices = c(
                       "ENSG00000000003.15"="ENSG00000000003.15",
                       "ENSG00000000005.6"="ENSG00000000005.6",
                       "ENSG00000000419.13"="ENSG00000000419.13",
                       "ENSG00000000457.14"="ENSG00000000457.14",
                       "ENSG00000000460.17"="ENSG00000000460.17",
                       "ENSG00000000938.13"="ENSG00000000938.13",
                       "ENSG00000000971.16"="ENSG00000000971.16",
                       "ENSG00000001036.14"="ENSG00000001036.14",
                       "ENSG00000001084.13"="ENSG00000001084.13",
                       "ENSG00000001167.14"="ENSG00000001167.14",
                       "ENSG00000001460.18"="ENSG00000001460.18",
                       "ENSG00000001461.17"="ENSG00000001461.17",
                       "ENSG00000001497.18"="ENSG00000001497.18",
                       "ENSG00000001561.7"="ENSG00000001561.7",
                       "ENSG00000001617.12"="ENSG00000001617.12",
                       "ENSG00000001626.16"="ENSG00000001626.16",
                       "ENSG00000001629.10"="ENSG00000001629.10",
                       "ENSG00000001630.17"="ENSG00000001630.17",
                       "ENSG00000001631.16"="ENSG00000001631.16",
                       "ENSG00000002016.18"="ENSG00000002016.18",
                       "ENSG00000002079.14"="ENSG00000002079.14",
                       "ENSG00000002330.14"="ENSG00000002330.14",
                       "ENSG00000002549.12"="ENSG00000002549.12",
                       "ENSG00000002586.20"="ENSG00000002586.20",
                       "ENSG00000002586.20_PAR_Y"="ENSG00000002586.20_PAR_Y",
                       "ENSG00000002587.10"="ENSG00000002587.10",
                       "ENSG00000002726.21"="ENSG00000002726.21",
                       "ENSG00000002745.13"="ENSG00000002745.13",
                       "ENSG00000002746.15"="ENSG00000002746.15",
                       "ENSG00000002822.15"="ENSG00000002822.15",
                       "ENSG00000002834.18"="ENSG00000002834.18",
                       "ENSG00000002919.15"= "ENSG00000002919.15",
                       "ENSG00000002933.9"="ENSG00000002933.9",
                       "ENSG00000003056.8"="ENSG00000003056.8",
                       "ENSG00000003096.14"="ENSG00000003096.14",
                       "ENSG00000003137.8"= "ENSG00000003137.8",
                       "ENSG00000003147.19"="ENSG00000003147.19",
                       "ENSG00000003249.15"="ENSG00000003249.15",
                       "ENSG00000003393.15"= "ENSG00000003393.15",
                       "ENSG00000003400.15"="ENSG00000003400.15",
                       "ENSG00000003402.20"="ENSG00000003402.20",
                       "ENSG00000003436.16"= "ENSG00000003436.16",
                       "ENSG00000003509.16"="ENSG00000003509.16",
                       "ENSG00000003756.17"="ENSG00000003756.17",
                       "ENSG00000003987.14"="ENSG00000003987.14",
                       "ENSG00000003989.18"="ENSG00000003989.18",
                       "ENSG00000004059.11"= "ENSG00000004059.11",
                       "ENSG00000004139.14"="ENSG00000004139.14",
                       "ENSG00000004142.12"="ENSG00000004142.12" ),
                     selected = ""),

                   radioButtons(
                     inputId="choices",
                     label = "Please choose one of the below choices",
                     choices = c("lasso"="lasso", 
                                 "ridge"="ridge"),




                     plotOutput(outputId = "hist")
                   )
                 )
)




server <- function(input,output) {

  plotOutput$hist <- renderPlot({




    newx <- data.matrix(metadata[1:20,1:2])
    newy <- metadata$ENSG00000000003.15[1:20]

    library(glmnet)

    #perform k-fold cross-validation to find optimal lambda value
    dataa_shiny == cv.glmnet(newx, newy, alpha = 1)

    #find optimal lambda value that minimizes test MSE
    plot_shiny <- dataa_shiny$lambda.min




    #produce plot of test MSE by lambda value
    plot(dataa_shiny) })}

shinyApp(ui=ui, server=server)

but there is a error like

Error in plotOutput$hist <- renderPlot({ : 
  object of type 'closure' is not subsettable

Answer 1

[Meisam]

Welcome to biostars, since your example is not reproducible it is not possible to help you, but I noticed a couple vital errors in your code: First, in the server you have to address the outputs with the output name prefix that you specify in your server function, so here for your hist object it should be output$hist not plotOutput$hist, it does not mean anything for the app. Second, again in your server side you have a line doing cross validation with cv.glmnet(), instead of assigning the result to the dataa_shiny object (with either <- or =) you logically evaluate it (==) which again does not mean anything for your subsequent code.

Anyways for these kinds of questions you better use programming Q&A forums like stackoverflow rather than biostars since your question is not related to bioinformatics or computational biology.

[Sude]

Thank you so much...