Modify my rChart based on a reactive input? - r

Question

I am having trouble with some code that I've written.
Here is a sample of the dataset: https://docs.google.com/spreadsheets/d/1C_P5xxzYr7HOkaZFfFiDhanqDSuSIrd2UkiC-6_G2q0/edit?usp=sharing
Objective:
I have a dataset that contains a column of Purchase_Month, candy and freq of the number of times that type of candy was purchased in that given month.
I have an rPlot which I was to change based on the chosen Candy bar in the SelectInput. And output a line chart based on the number of times that candy was purchased that month.
I have my current code below, but it tells me that candyCount is not found.
## ui.R ##
library(shinydashboard)
library(rCharts)
dashboardPage(
dashboardHeader(title = "Dashboard"),
dashboardSidebar(
width = 150,
sidebarMenu(
menuItem("Dashboard", tabName = "dashboard", icon = icon("bar-chart"))
)
),
dashboardBody(
sidebarPanel(
htmlOutput("candy")
),
mainPanel(
showOutput("plot2", "polycharts")
))
)
##server.R##
library(rCharts)
library(ggplot2)
library(ggvis)
server <- function(input, output, session) {
output$candy <- renderUI({
available2 <- dataset[(dataset$candy == input$candy), "candy"]
selectInput(
inputId = "candy",
label = "Choose a candy: ",
choices = sort(as.character(unique(available2))),
selected = unique(available2[1])
)
})
observeEvent(input$candy, {
candyChoice<- toString(input$customer_issue)
print(candyChoice)
candyCount<- dataset[dataset$candy == candyChoice, ]
})
})
output$plot2 <- renderChart2({
p2 <- rPlot(freq~purchase_month, data = candyCount, type = 'line')
p2$guides(y = list(min = 0, title = ""))
p2$guides(y = list(title = sprintf("%s Claims",input$candy)))
p2$addParams(height = 300, dom = 'chart2')
return(p2)
})
}
Updated Data: Why wouldn't this work?
candyCount<- reactive({
dataset[dataset$candy == input$candy, ]
})
output$plot2 <- renderChart2({
p2 <- rPlot(freq~purchase, data = candyCount(), type = 'line')
p2$guides(y = list(min = 0, title = ""))
p2$guides(y = list(title = ""))
p2$addParams(height = 300, dom = 'chart2')
return(p2)
})

Answer 1

output$candy <- renderUI({
available2 <- dataset[(dataset$candy == input$candy), "candy"]
selectInput(
inputId = "candy",
label = "Choose a candy: ",
choices = sort(as.character(unique(available2))),
selected = unique(available2[1])
)
})
In the above you are trying to subset by an input, which is inside your output. The selectInput needs to be inside UI.R.
A working basic example you may find useful.
library(shiny)
df <- read.csv("/path/to/my.csv")
ui <- shinyUI(pageWithSidebar(
headerPanel('Candy Data'),
sidebarPanel(
selectInput('candy', 'Candy', unique(as.character(df[,2])), selected = "Twix")
),
mainPanel(
plotOutput('plot1')
)
))
server <- shinyServer(function(input, output, session) {
selectedData <- reactive({
df[which(df[,2] == input$candy),3]
})
output$plot1 <- renderPlot({
barplot(selectedData())
})
})
shinyApp(ui, server)
In the above example the ui renders a selectInput which has the ID candy. The value, i.e the candy selected is now assigned to input$candy scope. In server we have a reactive function watching for any input change. When the user selects a new candy this function, df[which(df[,2] == input$candy),3] is saying "subset my data frame, df, by the new input$candy". This is now assigned to the selectedData(). Finally we render then boxplot.
EDIT
server.R
require(rCharts)
options(RCHART_WIDTH = 500)
df <- read.csv("path/to/my.csv")
shinyServer(function(input, output, session) {
selectedData <- reactive({
df[which(df[,2] == input$candy),]
})
output$plot1 <- renderChart({
p <- rPlot(freq~purchase_month, data = selectedData(), type = "line")
p$addParams(dom = 'plot1')
return(p)
})
})
ui.R
require(rCharts)
options(RCHART_LIB = 'polycharts')
shinyUI(pageWithSidebar(
headerPanel('Candy Data'),
sidebarPanel(
selectInput('candy', 'Candy', unique(as.character(df[,2])), selected = "Twix")
),
mainPanel(
showOutput('plot1', 'polycharts')
)
))
save files in directory and then runApp.

Answer 2

At available2 you're filtering the data about a selected candy with dataset$candy == input$candy. But you use the same available2 to determine which are the choices at selectInput. I'm guessing you wanted: available2 <- dataset[, "candy"].