Shiny: Show buttons only after file has been uploaded
This code worked for me
ui.R
# ui.R
library(shiny)
shinyUI(fluidPage(
titlePanel("Multiple Linear Regression"),
sidebarLayout(
sidebarPanel(
fileInput('file1', 'Choose CSV File',
accept=c('text/csv',
'text/comma-separated-values,text/plain',
'.csv')),
tags$hr(),
uiOutput("dependent"),
uiOutput("independents"),
tags$hr(),
uiOutput('ui.action') # instead of conditionalPanel
),
mainPanel(
verbatimTextOutput('contents')
)
)
))
server.R
# server.R
library(shiny)
shinyServer(function(input, output) {
filedata <- reactive({
infile <- input$file1
if (is.null(infile)){
return(NULL)
}
read.csv(infile$datapath)
})
output$dependent <- renderUI({
df <- filedata()
if (is.null(df)) return(NULL)
items=names(df)
names(items)=items
selectInput("dependent","Select ONE variable as dependent variable from:",items)
})
output$independents <- renderUI({
df <- filedata()
if (is.null(df)) return(NULL)
items=names(df)
names(items)=items
selectInput("independents","Select ONE or MANY independent variables from:",items,multiple=TRUE)
})
output$contents <- renderPrint({
input$action
isolate({
df <- filedata()
if (is.null(df)) return(NULL)
fmla <- as.formula(paste(input$dependent," ~ ",paste(input$independents,collapse="+")))
summary(lm(fmla,data=df))
})
})
output$ui.action <- renderUI({
if (is.null(input$file1)) return()
actionButton("action", "Press after reading file and selecting variables")
})
})
Here's the working ShinyApp and the final version of both ui.R and server.R based on all the suggestions provided by Marat.
First the ui.R
# ui.R
library(shiny)
shinyUI(fluidPage(
titlePanel("Multiple Linear Regression with R/Shiny"),
sidebarLayout(
sidebarPanel(
p("Please upload a CSV formatted file with your data."),
fileInput('file1', label='Click button below to select the file in your computer.',
accept=c('text/csv',
'text/comma-separated-values,text/plain',
'.csv')),
tags$hr(),
uiOutput("dependent"),
uiOutput("independents"),
tags$hr(),
uiOutput('ui.action') # instead of conditionalPanel
),
mainPanel(
p("Here's the output from your regression:"),
verbatimTextOutput('contents')
)
)
))
and server.R
# server.R
library(shiny)
shinyServer(function(input, output) {
filedata <- reactive({
infile <- input$file1
if (is.null(infile)){
return(NULL)
}
read.csv(infile$datapath)
})
output$ui.action <- renderUI({
if (is.null(filedata())) return()
actionButton("action", "Run regression")
})
output$dependent <- renderUI({
df <- filedata()
if (is.null(df)) return(NULL)
items=names(df)
names(items)=items
selectInput("dependent","Now select ONE variable as dependent variable from:",items)
})
output$independents <- renderUI({
df <- filedata()
if (is.null(df)) return(NULL)
items=names(df)
names(items)=items
selectInput("independents","Also select ONE or MANY independent variables in the box below. You can change your selection several times:",items,multiple=TRUE)
})
output$contents <- renderPrint({
if (is.null(input$action)) return()
if (input$action==0) return()
isolate({
df <- filedata()
if (is.null(df)) return(NULL)
fmla <- as.formula(paste(input$dependent," ~ ",paste(input$independents,collapse="+")))
summary(lm(fmla,data=df))
})
})
})
Once again thanks for your help Marat.