问题
Let's say I have created 10 selectInput
dropdowns for a multi plot export and these selectInputs
are called "xaxis_1", "xaxis_2", ..... , "xaxis_10"
for a single 1 I can write:
if(!is.null(input$xaxis_1)) { .... do stuff }
to stop it running export when the user hasn't entered any name, and presses submit, to avoid crashes.
A bit more general you can check this:
if(!is.null(input[[paste('xaxis', i, sep = '_')]])) { ...}
how can you write it elegantly so that 1 line of code checks whether ANY of the 1:10 input[[...]] is empty, i.e. NULL?
The nr of inputs depends on how many plots the user wants to export per file, so all is build with lapply(1:input$nrofplots, function(i) { .... } renderUI
structure, and my if statement needs to have the same flexibility of 1:n
In a situation like below in the image, pressing Initiate export
should give a sweetalert
(got that covered) saying there is at least 1 value missing
回答1:
Here a snippet I used in the UI side to validate the user's inputs.
library(shiny)
library(shinyjs)
ui <- fluidPage(
useShinyjs(), # Set up shinyjs
numericInput('axis1','Val 1',1),
numericInput('axis2','Val 2',1),
numericInput('axis3','Val 3',1),
actionButton('Go','Plot')
)
server <- function(input, output, session) {
#Try 1, space, AAA and check what shiny will return
observe(print(input$axis1))
observe({
All_Inputs <- vapply(paste0('axis',1:3),
function(x){isTruthy(input[[x]])},
logical(1))
All_InputsCP <- all(All_Inputs)
shinyjs::toggleState(id="Go", condition = All_InputsCP) #This is to make the button Go able or disable according to condition All_InputsCP #
})
}
shinyApp(ui, server)
I hope it helps.
来源:https://stackoverflow.com/questions/55206206/test-whether-any-input-in-a-set-of-numbered-input-objects-in-r-shiny-is-empty