Trying to pull individual values from a checkboxGroupInput in Shiny

Question

I'm very new to Shiny and R, and I'm having an issue. I'm writing an app that reads a csv file containing a list of athlete names and all their collected information, i.e speed, height, weight, etc..

I'm trying to allow for updating that information. So I created a vector containing 5 column values from the rows for a selected athlete. This information is their name, class year, sport, coach and entry date. I've got the checkBoxGroupInput working. The problem is once I have that returned value from the check box I can't split apart the information to be able to select that specific row from the dataframe for updating.

So here's some of the important code:

ui <- fluid panel
   
#other code is here that is working. Just focusing on this code for this issue

      tabPanel(title = "Update Info", value = "updateAth",
                 tags$h3("Update Athlete's Information"),
                 sidebarLayout(
                    sidebarPanel(
                      selectizeInput("updtAth","Choose Ahtlete",choices = unique(athletes$ATHLETE),options = list(placeholder = '', onInitialize = I('function() {this.setValue("");}'))),
                      br(),
                      #action button to select the patient
                      actionButton("selectAth","Select"),
                      br(),
                      uiOutput("nextSteps")
                    ), #end sidebarPanel
                    mainPanel(
                      uiOutput("moreSteps"),
                    ) #end main panel
            
               ) 
      ) 
) 

server <- function(input,output,session) { 



  observeEvent(input$selectAth, {


      athDF <- data.frame(subset.data.frame(athletes,athletes$ATHLETE == input$updtAth, select = c("CLASSMAN","SPORT","COACH","DATE")))
      rws <- nrow(athDF)
      values <- vector(length = rws)
      
      #create the list of choices in a for loop
      for (i in 1:rws) {
        values[i] <- paste(input$updtAth,athDF[i,1],athDF[i,2],athDF[i,3],athDF[i,4])
      } # end for loop
      
      output$nextSteps <- renderUI({
        tagList(
          br(),
          checkboxGroupInput("row","Choose the row to update",choices = as.list(values)),
          br(),
          actionButton("updateRow","Update Row")
        ) #end tagList
      }) # end output renderUI
################  this is the first thing I tried and I get this as my output --  "this is it NA Harry, Barry"
        

        rowToString <- renderText(input$row)
        updtclass <- rowToString()[2]  #this value should be 3



#####################When I try this I get this as my output ---  "this is it Dolphin, Barry "
        

        updtclass <- input$row[2]  #this value should be 4
         output$text <- renderText({paste("this is the it", updtclass," ",input$updtAth)})
     
    
      observeEvent(input$updateRow, {
          output$moreSteps <- renderUI({
          fluidRow (
            #dataTableOutput('getTable'),
            textOutput('text'),
            br(),
            tags$h3("Only fill in the attributes that need to be changed"),
            
            
            column(3,
                 textInput("upDtht","Height",value = NULL,width = '100px', placeholder = "in inches"),
                 textInput("upDtwt","Weight", value = NULL, width = '100px'),
                 textInput("upDtsport","Sport", value = NULL, width = '100px'),
                 textInput("upDtspeed","Speed", value = NULL, width = '100px'),
                 textInput("upDtagility","Agility", value = NULL, width = '100px')
            ), #end column
            column(
                4,offset = -1,
                textInput("upDtcmj","CMJ",value = NULL, width = '100px'),
                textInput("upDtsj","SJ",value = NULL, width = '100px'),
                textInput("upDtnotes","Notes", value = NULL, width = '800px'),
                textInput("upDtdate","Date", value = format(Sys.Date(),format="%m/%d/%Y"), width = '100px'),
                br(),
                actionButton("update","Update")
          ), #end next column
          
        ) #end fluid row

        }) # end renderUI moreSteps
        
      }) #end observe Event updateRow
      
      
      observeEvent(input$update, { 
          #i'll work this out later

      ) #end observe Event update
      
    } #end work inside first observeEvent
    
  ) #end observeEvent update info
}

I just can't figure out how to pull each value from the check box. An Example of what the data in the checkbox will return is:

"Harry, Barry" "3" "Basketball" "Coach Jones" "07/15/2019"

My goal is to pull each individual value and put it in a variable to use to pull that specific row out of the dataframe so I can get the end user to update it. athlete = Harry, Barry, classyear = 3, sport = Basketball, coach = Coach Jones, updtDate = 07/15/2019

I hope this makes sense.

Answer 1

input$checkBoxGroupInput[1] will give you the first, input$checkBoxGroupInput[2] the second and so on. In summary the output of a checkBoxGroupInput is a vector.

Here is a minimal example:

library(shiny)

ui <- fluidPage(
    
    checkboxGroupInput("checkboxGroupInput","checkboxGroupInput", choices = c(1, 2, 3))
    
)

server <- function(input, output, session) {
    
    #Runs when checkboxGroupInput is changed
    observeEvent(input$checkboxGroupInput, {
        
        #Clear console
        cat("\014") 
        
        #Print the selection(s) of checkboxGroupInput to the console
        print(paste('1st value:', input$checkboxGroupInput[1]))
        print(paste('2nd value:', input$checkboxGroupInput[2]))
        print(paste('3rd value:', input$checkboxGroupInput[3]))
        
    })
    
}

shinyApp(ui, server)

I can't run your code, but it sounds like a checkBoxGroupInput might not be the right input in this case. Perhaps a series of drop down boxes would be more useful.