Plot the boxplot by using check box in shiny app - r

Question

I'd like to use check box input to allow to show different island levels (within the categorical variable selected for the x-axis) with separate boxplots and different colors with a legend. But if this check box is not selected, I just want to show boxplot without fill=legend that is:
ggplot(dat(), aes_string(x = isolate(input$xaxis), y = input$yaxis)) +
geom_boxplot()
This R code is what I tried to use but It didn't work. Could you please help me to solve or tell me what makes error with my R code?
Thank you in advance
library(shiny)
library(palmerpenguins)
library(ggplot2)
library(dplyr)
penguin <- penguins
penguin$year <- as.factor(penguin$year)
ui <- fluidPage(
titlePanel("Data Visualisation of Penguins Data"),
sidebarPanel(
selectInput("yaxis",
label = "Choose a y-axis variable to display",
choices = list("bill_length_mm",
"bill_depth_mm",
"flipper_length_mm",
"body_mass_g"),
selected = "bill_length_mm"),
selectInput("xaxis",
label = "Choose a x-axis variable to display",
choices = c("species",
"sex",
"year"),
selected = "sex"),
checkboxGroupInput("islandlevels",
label = "Check to display different island levels",
choices = c("island"),
selected = NULL),
br(), br(),
selectInput("species",
label = "Choose species to view separate plot",
choices = list("Adelie",
"Chinstrap",
"Gentoo"),
selected = NULL)),
mainPanel(
plotOutput("plot1"),
br(), br(),
plotOutput("plot2")
)
)
server <- function(input, output){
dat <- reactive({
if(input$xaxis == "sex") penguin[!is.na(penguin$sex),] else penguin
})
output$plot1 <- renderPlot({
if(input$islandlevels == "island") {
req(penguin, input$xaxis, input$yaxis)
ggplot(dat(), aes_string(x = isolate(input$xaxis), y = input$yaxis, fill=island)) +
geom_boxplot()
}
if(input$islandlevels = NULL) {
req(penguin, input$xaxis, input$yaxis)
ggplot(dat(), aes_string(x = isolate(input$xaxis), y = input$yaxis)) +
geom_boxplot()}
})
}
shinyApp(ui = ui, server = server)

Answer 1

As long as you don't want any other checkbox inputs you could use a checkboxInput instead of a checkboxGroupInput which makes checking a bit easier.
One issue in your server was that you used island instead of "island". Additionally you can simplify your code a little bit by using fill <- if (input$islandlevels) "island" which will return NULL is the the checkbox was not checked and "island" otherwise. This way you can handle both case with only one ggplot statement .
The full reproducible code:
library(shiny)
library(palmerpenguins)
library(ggplot2)
library(dplyr)
penguin <- penguins
penguin$year <- as.factor(penguin$year)
ui <- fluidPage(
titlePanel("Data Visualisation of Penguins Data"),
sidebarPanel(
selectInput("yaxis",
label = "Choose a y-axis variable to display",
choices = list("bill_length_mm",
"bill_depth_mm",
"flipper_length_mm",
"body_mass_g"),
selected = "bill_length_mm"),
selectInput("xaxis",
label = "Choose a x-axis variable to display",
choices = c("species",
"sex",
"year"),
selected = "sex"),
checkboxInput("islandlevels",
label = "Check to display different island levels",
value = FALSE),
br(), br(),
selectInput("species",
label = "Choose species to view separate plot",
choices = list("Adelie",
"Chinstrap",
"Gentoo"),
selected = NULL)),
mainPanel(
plotOutput("plot1"),
br(), br(),
plotOutput("plot2")
)
)
server <- function(input, output){
dat <- reactive({
if(input$xaxis == "sex") penguin[!is.na(penguin$sex),] else penguin
})
output$plot1 <- renderPlot({
req(penguin, input$xaxis, input$yaxis)
fill <- if (input$islandlevels) "island"
ggplot(dat(), aes_string(x = isolate(input$xaxis), y = input$yaxis, fill = fill)) +
geom_boxplot()
})
}
shinyApp(ui = ui, server = server)