Hello, I have been searching for tutorials on how to reactively plot user-uploaded data in Shiny.
Following tutorials (and comments in this community), I've figured out how to upload a CSV file and how to make plots from CSV files stored in the working directory. However, I can't seem to successfully make plots based whatever CSV file was uploaded.
I found the most comprehensive try to be this thread, which suggests this should work with the mtcars or iris datasets.
I try mtcars.csv, and the table uploads but the plot does not render. How can I make this work?
Code:
library(shiny)
library(datasets)
ui <- shinyUI(fluidPage(
titlePanel("Column Plot"),
tabsetPanel(
tabPanel("Upload File",
titlePanel("Uploading Files"),
sidebarLayout(
sidebarPanel(
fileInput('file1', 'Choose CSV File',
accept=c('text/csv',
'text/comma-separated-values,text/plain',
'.csv')),
# added interface for uploading data from
# http://shiny.rstudio.com/gallery/file-upload.html
tags$br(),
checkboxInput('header', 'Header', TRUE),
radioButtons('sep', 'Separator',
c(Comma=',',
Semicolon=';',
Tab='\t'),
','),
radioButtons('quote', 'Quote',
c(None='',
'Double Quote'='"',
'Single Quote'="'"),
'"')
),
mainPanel(
tableOutput('contents')
)
)
),
tabPanel("First Type",
pageWithSidebar(
headerPanel('My First Plot'),
sidebarPanel(
# "Empty inputs" - they will be updated after the data is uploaded
selectInput('xcol', 'X Variable', ""),
selectInput('ycol', 'Y Variable', "", selected = "")
),
mainPanel(
plotOutput('MyPlot')
)
)
)
)
)
)
server <- shinyServer(function(input, output, session) {
# added "session" because updateSelectInput requires it
data <- reactive({
req(input$file1) ## ?req # require that the input is available
inFile <- input$file1
# tested with a following dataset: write.csv(mtcars, "mtcars.csv")
# and write.csv(iris, "iris.csv")
df <- read.csv(inFile$datapath, header = input$header, sep = input$sep,
quote = input$quote)
# Update inputs (you could create an observer with both updateSel...)
# You can also constraint your choices. If you wanted select only numeric
# variables you could set "choices = sapply(df, is.numeric)"
# It depends on what do you want to do later on.
updateSelectInput(session, inputId = 'xcol', label = 'X Variable',
choices = names(df), selected = names(df))
updateSelectInput(session, inputId = 'ycol', label = 'Y Variable',
choices = names(df), selected = names(df)[2])
return(df)
})
output$contents <- renderTable({
data()
})
output$MyPlot <- renderPlot({
# for a histogram: remove the second variable (it has to be numeric as well):
# x <- data()[, c(input$xcol, input$ycol)]
# bins <- nrow(data())
# hist(x, breaks = bins, col = 'darkgray', border = 'white')
# Correct way:
# x <- data()[, input$xcol]
# bins <- nrow(data())
# hist(x, breaks = bins, col = 'darkgray', border = 'white')
# I Since you have two inputs I decided to make a scatterplot
x <- data()[, c(input$xcol, input$ycol)]
plot(x)
})
})
shinyApp(ui, server)
