Hello,
So I was curious to what exactly "!!" and "!!!" does in the next bit of code. It helps me get the list object into the right format for the select function but I would like to know what is technically happening (I did check in Advanced R as well)
## Only run examples in interactive R sessions
if (interactive()) {
library(ggplot2)
# single selection
shinyApp(
ui = fluidPage(
varSelectInput("variable", "Variable:", mtcars),
plotOutput("data")
),
server = function(input, output) {
output$data <- renderPlot({
ggplot(mtcars, aes(!!input$variable)) + geom_histogram()
})
}
)
# multiple selections
## Not run:
shinyApp(
ui = fluidPage(
varSelectInput("variables", "Variable:", mtcars, multiple = TRUE),
tableOutput("data")
),
server = function(input, output) {
output$data <- renderTable({
if (length(input$variables) == 0) return(mtcars)
mtcars %>% dplyr::select(!!!input$variables)
}, rownames = TRUE)
}
)
## End(Not run)
}