R Shiny - checkGroup and ggplot

Question

I am having a bit of trouble with a basic thing I am trying to create in Shiny. I want the user to select which variables will be plotted and based on that entry the appropriate subset of the data will be made and plotted.

shinyServer(function(input, output) {


output$value <- renderPrint({ input$checkGroup })

output$vehPlot <- renderPlot({

output$vehPlot <- reactivePlot(function() {

  if (input$variable == "pur") {
    # am

     if(!is.na(input$checkGroup[1]==1 & input$checkGroup[2]==2 & input$checkGroup[3]==3)) { #all check boxes

      vehData <- data.frame(newp[ which(newp$type=='2WD' | newp$type=='4WD'| newp$type=='ATV'), ])
    }

    else if(!is.na(input$checkGroup[1]==1)) { #only check box one 

      vehData <- data.frame(newp[ which(newp$type=='2WD'), ])
    }

    else if(!is.na(input$checkGroup[1]==2)) { #only check box two

      vehData <- data.frame(newp[ which(newp$type=='4WD'), ])
    }


    else if(!is.na(input$checkGroup[1]==3)) {   #only check box three

      vehData <- data.frame(newp[ which(newp$type=='ATV'), ])
    }

    else{

      vehData <- data.frame(Date=as.Date(character()),
                            File=character(), 
                            User=character(), 
                            stringsAsFactors=FALSE) 
    }

  }

  else {
    # cyl and gear
    vehData <- data.frame(new)
  }

  p <- ggplot(data=vehData,aes(x=vehData$year,y=vehData$num, group=vehData$type,colour=vehData$type)) + 
    geom_line()+
    geom_point() 

  print(p)
})

}) })

So as it stands, only 2WD variable can be plotted on its own. Whenever I select 4WD on its own for example, the correct subset is not being made and all three are plotted.

I don't believe it is an issue with the reactive functions but I could be wrong or maybe not accessing the checkGroup output correctly. Also being newish to Shiny doesn't help.

Cheers.