Validates that dataset contains specific variable — validate_has

Usage

validate_has_variable(data, varname, msg)

Arguments

data: a data.frame
varname: name of variable in data
msg: message to display if data does not include varname

Details

This function is a wrapper for shiny::validate.

Examples

data <- data.frame(
  one = rep("a", length.out = 20),
  two = rep(c("a", "b"), length.out = 20)
)
ui <- fluidPage(
  selectInput(
    "var",
    "Select variable",
    choices = c("one", "two", "three", "four"),
    selected = "one"
  ),
  verbatimTextOutput("summary")
)

server <- function(input, output) {
  output$summary <- renderText({
    validate_has_variable(data, input$var)
    paste0("Selected treatment variables: ", paste(input$var, collapse = ", "))
  })
}
if (interactive()) {
  shinyApp(ui, server)
}