Shiny: how to use checkBoxGroupInput() to reactively change a bar chart - r

Question

I'm pretty new to shiny and am struggling on how to use check boxes to update values in a bar chart. The idea I'm after is when a user ticks on a check box, a numerical value is generated that will be added to an aggregate from other inputs to make a bar chart. Here is the code I have gotten to work so far:
library(shiny)
ui <- fluidPage(
titlePanel("TCO Calculator"),
mainPanel(
sidebarPanel(
helpText("Product 1 information:"),
numericInput(
inputId = "price_1",
label = "Purchase Price",
value = "0",
min = 0,
width = '50%'
),
numericInput(
inputId = "install_1",
label = "Installation cost",
value = "0",
min = 0,
width = '50%'
),
selectInput("disposal_1", "Disposal Cost",
choices = list(Buyback = (10),
Dump = (30),
Reuse = (5)),
width = '50%'),
checkboxGroupInput("maint_1", "Maintenance:",
choices = c("Waxing",
"Stripping", "Burnishing"),
selected = NULL)
),
sidebarPanel(
helpText("Product 2 information:"),
numericInput(
inputId = "price_2",
label = "Purchase Price",
value = "0",
min = 0,
width = '50%'
),
numericInput(
inputId = "install_2",
label = "Installation cost",
value = "0",
min = 0,
width = '50%'
),
# make list?
selectInput("disposal_2", "Disposal Cost",
choices = list(Buyback = (10),
Dump = (30),
Reuse = (5)),
width = '50%'),
checkboxGroupInput("maint_2", "Maintenance:",
choices = NULL,
selected = NULL,
inline = FALSE,
width = NULL,
choiceNames = c("Waxing",
"Stripping", "Burnishing"),
choiceValues = c(10, 20, 40))
),
plotOutput("costPlot")))
server <- function(input, output, session) {
# aggregate inputs into reactive bar chart values.
select_price <- reactive({
c(input$price_1 + input$install_1
+ as.numeric(input$disposal_1),
input$price_2 + input$install_2 +
as.numeric(input$disposal_2))
})
# Bar chart.
my_bar <- output$costPlot <- renderPlot({
barplot(select_price(),
beside = T,
border=F,
las=2 ,
col=c(rgb(0.3,0.1,0.4,0.6) ,
rgb(0.3,0.5,0.4,0.6)) ,
space = 3,
ylab = "Total cost per square foot, US Dollar")
abline(v=c(4.9 , 6.1) , col="grey")
legend("top", legend = c("Product 1", "Product 2" ),
col = c(rgb(0.3,0.1,0.4,0.6),
rgb(0.3,0.5,0.4,0.6)),
bty = "n",
pch=20 , pt.cex = 4,
cex = 1.6, horiz = FALSE,
inset = c(0.05, 0.05))
my_bar
})
}
shinyApp(ui = ui, server = server)
I've been successful with the numericInput and selectInput stuff so far, I am having trouble putting together a concise way to include check boxes (with corresponding numeric values) into a reactive function that I can path into select_price(), like I have done with the numeric and selectBox stuff. Things go sideways when I try to map from other examples. I feel like there is an elegant, or in least working solution that exists. Any insight towards how to solve this would be so appreciated, thanks!

Answer 1

I am not sure whether this entirely solves all your problems but try this:
For maint_2, you correctly separate choiceNames and choiceValues. For maint_1 you dont't
checkboxGroupInput("maint_1", "Maintenance:",
choices = NULL,
selected = NULL,
choiceNames = c("Waxing", "Stripping", "Burnishing"),
choiceValues = c(10, 20, 40))
Then you can add input$maint_1 and input$maint_2 to your reactive (also wrapped in as.numeric(). I also use sum for + as you don't have a default for input$maint_1 and input$maint_2. sum evaluates this to 0 while + throws an error.
select_price <- reactive({
c(sum(input$price_1, input$install_1, as.numeric(input$disposal_1), as.numeric(input$maint_1)),
sum(input$price_2, input$install_2, as.numeric(input$disposal_2), as.numeric(input$maint_1)))
})