Shiny app with reactive data call from server - r

Question

I'm trying to make a plot with reactive data from the server. Unfortunately I can't get the plot to work. I'm getting an error like: "Error:EXPR must be a length 1 vector". I tried different styles of plots and different libraries: Quantmod, ggplot, so on. Any suggestions?
Server:
library(shiny)
Dat<-read.csv("A:\\home\\Documents\\Franchise_Failureby_Brand2011.csv", sep=';')
names(Dat)[1]<-paste("Brand")
names(Dat)[2]<-paste("Failure")
names(Dat)[3]<-paste("Disbursement")
names(Dat)[4]<-paste("Disb$X$1000")
names(Dat)[5]<-paste("Chgoff")
Dat1<-Dat[is.na(Dat)==FALSE,]
Dat<-Dat1[1:578,]
# Define server logic required to draw a histogram
shinyServer(function(input, output) {
DatSv <- reactive({
Value <- switch(input$Value,
"Failure"= Dat$Failure[1:10],
"Disbursement"=Dat$Disbursement[1:10],
"Disb$X$1000"=Dat$`Disb$X$1000`[1:10],
"Chgoff"=Dat$Chgoff[1:10])
Brand<-Dat$Brand[1:10]
Brand(input$Value)
})
# Generate plot
output$plot1 <- renderPlot({
library("quantmod")
hist(DatSv(),
main=paste('r', Value, '(', Brand, ')', sep=''))
})
# Generate summary of data
output$summary<-renderPrint({
summary(Dat)
})
})
UI:
library(shiny)
shinyUI(fluidPage(
titlePanel("Plot Franchise Failure"),
sidebarLayout(
sidebarPanel(
radioButtons("n", "Chose output Y Axis:",
c("Failure" ,
"Disbursement",
"Disb$X$1000" ,
"Chgoff" )),
checkboxInput("show_xlab", "Show/Hide X Axis Label", value=TRUE),
checkboxInput("show_ylab", "Show/Hide Y Axis Label", value=TRUE),
checkboxInput("show_title", "Show/Hide Title")
),
mainPanel(
tabsetPanel(
type = "tabs",
tabPanel("Plot", plotOutput("plot1")),
tabPanel("Summary", verbatimTextOutput("summary"))
)
)
)
)
)

Answer 1

Hi the problem comes from connecting the inputs in the UI with the server. In the UI you have given the inputid = "n" for the radioButtons. That means we can get the Value of the Radiobuttons with input$n and not input$Value. The later is always NULL since there is no input with inputid = "Value". I had some other small problems with your code but here is a working version of the server code. I didn't modify the UI
library(shiny)
Dat<-read.csv("A:\\home\\Documents\\Franchise_Failureby_Brand2011.csv", sep=';')
names(Dat)[1]<-paste("Brand")
names(Dat)[2]<-paste("Failure")
names(Dat)[3]<-paste("Disbursement")
names(Dat)[4]<-paste("Disb$X$1000")
names(Dat)[5]<-paste("Chgoff")
Dat1<-Dat[is.na(Dat)==FALSE,]
Dat<-Dat1[1:578,]
# Define server logic required to draw a histogram
shinyServer(function(input, output) {
DatSv <- reactive({
switch(input$n,
"Failure"= gsub("%","",as.character( Dat$Failure)),
"Disbursement"=Dat$Disbursement,
"Disb$X$1000"=gsub("\\$","",as.character( Dat$`Disb$X$1000`)),
"Chgoff"=gsub("%","",as.character(Dat$Chgoff)))
})
# Generate plot
output$plot1 <- renderPlot({
library("quantmod")
hist(as.numeric(DatSv()),
main=paste('Histogram of ',input$n, sep=''),
xlab = input$n)
})
# Generate summary of data
output$summary<-renderPrint({
summary(Dat)
})
})