selecting among files already stored on shiny server - r

Question

I am new to R and Shiny and I have some data files stored on my Shiny server.
What I want to do is to choose a file based upon user selection and then read that file into a data frame.
I am currently getting an object not found error, although the name is being transferred properly to the server UI.
Here is some code, fisrt server.r
library(shiny)
library(datasets)
filenames<-list.files(path="~/qc",pattern="\\.csv$")
shinyServer(function(input,output){
output$choose_dataset<-renderUI({
selectInput("dataset","Data set",filenames)
})
output$data_table<-renderTable({
selFile<-get(input$dataset)
mydat<-read.csv(selFile$name,header=T)
head(mydat,50)
})
})
Here is the ui.r
library(shiny)
shinyUI(pageWithSidebar(
headerPanel(
"Files Selection"
),
sidebarPanel(
uiOutput("choose_dataset")
),
mainPanel(
tabsetPanel(
tabPanel("plot",plotOutput("plot"),id="myplot"),
tabPanel("Data",tableOutput("data_table"),id="myTab"),
id="Plot_Data"
)
)
))
Thanks for helping.

Answer 1

I made a few small changes and it works for me. Try and see this works for you as well.
In server.R I moved the selectInput() to UI.R, and I moved the filenames variable to UI.R as well.
Now, since input$dataset in a file, you don't get the get() command.
Server.R
library(shiny)
library(datasets)
shinyServer(function(input,output){
output$data_table<-renderTable({
#selFile<-get(input$dataset)
mydat<-read.csv(input$dataset, header=T)
head(mydat,50)
})
})
The updated UI.R
library(shiny)
filenames<-list.files(pattern="\\.csv$")
shinyUI(pageWithSidebar(
headerPanel(
"Files Selection"
),
sidebarPanel(
selectInput(inputId = "dataset",
label = "Choose Dataset",
filenames
)
),
mainPanel(
tabsetPanel(
tabPanel("plot",plotOutput("plot"),id="myplot"),
tabPanel("Data",tableOutput("data_table"),id="myTab"),
id="Plot_Data"
)
)
))
Try this and you shouldn't be getting the object not found error. You can use these files as the basis and build on top of these.
Hope this helps.