根据用户输入过滤数据范围

我有一个闪亮的应用程序，在散点图中绘制两个变量，并根据用户输入过滤 . 我试图让它，以便用户可以根据他们指定的范围过滤数据 . 但是，我只希望在填写字段时应用此过滤器，如果字段为空（null）则返回所有数据 . 例如，如果您启动我附加的代码，我希望用户能够检查“指定数据范围”复选框，当他们在min x输入框中输入4.8时，数据将被过滤掉，以便没有数据点现在考虑不到4.8 . 我准备的示例代码如下所示，我试图在中间附近评论 .

#Check packages to use in library
{
library('shiny') #allows for the shiny app to be used
library('ggvis') #allows for interactive ploting
}

alldata <- iris

#establish options for drop down menus
{
specieschoices <- unique(as.character(alldata$Species))
}
# UI

ui<-fluidPage(
titlePanel("Explorer"),
fluidRow(
column(4,
       wellPanel(
         h4("Apply Filters"),
         selectInput(inputId = "species", label="Select a Species:", choices = sort(specieschoices), selected="setosa", multiple = TRUE, selectize = TRUE)
       )),
column(8,
       ggvisOutput("plot1")
),
column(4,
       wellPanel(
         h4("Data Variables"),
         selectInput(inputId = "x", label="Select x-axis Variable:", choices=as.character(names(alldata[,1:4])),selected='Petal.Length', multiple = FALSE),
         selectInput(inputId = "y", label="Select y-axis Variable:", choices=as.character(names(alldata[,1:4])),selected='Petal.Width', multiple = FALSE)
       )),

column(4,
       wellPanel(
         checkboxInput(inputId = "datarange", label="Specify Data Ranges", value = FALSE),
         conditionalPanel(
           condition = "input.datarange == true",
           wellPanel(
             numericInput(inputId = "minxdata", label="Specify x axis min", value = -9999999999, step = 0.1),
             numericInput(inputId = "maxxdata", label="Specify x axis max", value = 9999999999, step = 0.1),
             numericInput(inputId = "minydata", label="Specify y axis min", value = -9999999999, step = 0.1),
             numericInput(inputId = "maxydata", label="Specify y axis max", value = 9999999999, step = 0.1)
           ))
       ))
))

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

#Set up reactive variables for ranges
filteredData <- reactive({

minX <- input$minxdata
maxX <- input$maxxdata
minY <- input$minydata
maxY <- input$maxydata

# Apply filters
m <- alldata %>% filter(
  `Species` %in% input$species

  ###############THIS IS THE PART THAT I NEED HELP WITH
  #This works as hardcoded with hypothetical user input of x=Petal.Length and y=Petal.Width
  ,
  Petal.Length >= minX,
  Petal.Length <= maxX,
  Petal.Width >= minY,
  Petal.Width <= maxY

  #This is does not work
  # ,
  # as.symbol(input$x) >= minX,
  # as.symbol(input$x) <= maxX,
  # as.symbol(input$y) >= minY,
  # as.symbol(input$y) <= maxY
  #####################################################

)
m <- droplevels(as.data.frame(m))
m
})

vis <- reactive({

#Plot Data with Visualization Customization
xvar <- prop("x", as.symbol(input$x))
yvar <- prop("y", as.symbol(input$y))

p1 = filteredData() %>%
  ggvis(x = xvar, y = yvar) %>%
  layer_points() %>%

  # Specifies the size of the plot
  set_options(width = 800, height = 450, duration = 0)
})

#Actually plots the data
vis %>% bind_shiny("plot1")
}

#Run the Shiny App to Display Webpage
shinyApp(ui=ui, server=server)

更新：

我认为我已经走上正轨，但是如果更改为> = 0，则min x和min y会过滤掉所有数据，如果更改，其他过滤器不会执行任何操作 .

paste0("`", input$x, "`") >= minX,
  paste0("`", input$x, "`") <= maxX,
  paste0("`", input$y, "`") >= minY,
  paste0("`", input$y, "`") <= maxY