r shiny selectInput - selectable classes in only one column - r

Question

I'm new to R and shiny. I have a problem that I could not solve.
I have a histogram where I want to make the classes separately selectable.
The classes are all in one column. To make them separately selectable, I did not succeed.
How do I get it to work?
Thanks a lot
## app.R ##
set.seed(24)
df <- data.frame(Class = sample(LETTERS[1:5], 30, replace = TRUE),
Amount = sample(5:20, 30, replace = TRUE),
stringsAsFactors= FALSE, check.names = FALSE)
server <- function(input, output) {
output$distPlot <- renderPlot({
hist(rnorm(input$obs), col = 'darkgray', border = 'white')
})
output$sum = renderPrint({
summary(df)
})
output$str = renderPrint({
str(df)
})
output$data = renderTable({
colm = as.numeric(input$var)
df[colm]
head(df)
})
output$myhist <- renderPlot({
colm = as.numeric(input$var)
hist(df$Amount, col =input$colour, xlim = c(0, max(df$Amount)), main = "Histogram", breaks = seq(0, max(df$Amount),l=input$bin+1),
xlab = names(df$Amount)
)}
)
}
ui <- fluidPage(
sidebarLayout(
sidebarPanel(
selectInput("var", label = "1. Select Class",
choices = c("A" = 1, "B" = 2, "C" = 3, "D"= 4, "E" = 5),
selected = 2),
sliderInput("bin", "2. Select the number of histogram BINs by using the slider below", min=5, max=25, value=15),
radioButtons("colour", label = "3. Select the color of histogram",
choices = c("Green", "Red",
"Blue"), selected = "Green")
),
mainPanel(
tabsetPanel(type="tab",
tabPanel("Plot", plotOutput("myhist")),
tabPanel("Summary", verbatimTextOutput("sum")),
tabPanel("Structure", verbatimTextOutput("str")),
tabPanel("Data", tableOutput("data"))
)
)
)
)
shinyApp(ui = ui, server = server)
I appreciate your help.

Answer 1

You have a few options:
Allow the selectInput to have multiple selections, by adding multiple = TRUE:
selectInput("var", label = "1. Select Class", choices = c("A" = 1, "B" = 2, "C" = 3, "D"= 4, "E" = 5), multiple = TRUE)
Use a checkbox group:
checkboxGroupInput('var', label = "1. Select Class", choices = c("A" = 1, "B" = 2, "C" = 3, "D"= 4, "E" = 5))
I recommend the 2nd option, using a checkbox group, as I believe they are easy for users to understand.
EDIT
As requested here is the full code, with the checkbox group linked to the chart:
## app.R ##
library(shiny)
set.seed(24)
df <- data.frame(Class = sample(LETTERS[1:5], 30, replace = TRUE),
Amount = sample(5:20, 30, replace = TRUE),
stringsAsFactors= FALSE, check.names = FALSE)
server <- function(input, output) {
output$distPlot <- renderPlot({
hist(rnorm(input$obs), col = 'darkgray', border = 'white')
})
output$sum = renderPrint({
summary(df)
})
output$str = renderPrint({
str(df)
})
output$data = renderTable({
colm = as.numeric(input$var)
df[colm]
head(df)
})
output$myhist <- renderPlot({
df_plot <- df[df$Class %in% input$var, ]
hist(df_plot$Amount, col = input$colour, xlim = c(0, max(df_plot$Amount)), main = "Histogram", breaks = seq(0, max(df_plot$Amount),l=input$bin+1),
xlab = names(df_plot$Amount)
)}
)
}
ui <- fluidPage(
sidebarLayout(
sidebarPanel(
checkboxGroupInput('var', label = "1. Select Class", choices = c("A", "B", "C", "D", "E"), selected = "B"),
sliderInput("bin", "2. Select the number of histogram BINs by using the slider below", min=5, max=25, value=15),
radioButtons("colour", label = "3. Select the color of histogram",
choices = c("Green", "Red",
"Blue"), selected = "Green")
),
mainPanel(
tabsetPanel(type="tab",
tabPanel("Plot", plotOutput("myhist")),
tabPanel("Summary", verbatimTextOutput("sum")),
tabPanel("Structure", verbatimTextOutput("str")),
tabPanel("Data", tableOutput("data"))
)
)
)
)
shinyApp(ui = ui, server = server)