Question

我想通过用户定义的y轴的值来为我的R Shiny中的条形图排序x轴（名称）。

 x_axis <- reactive({
        as.data.frame <- lpop$Name <- reorder(lpop$Name, lpop$MYE2016, 
FUN = mean)
      })

上面的代码创建了一个反应式变量，该变量在MYE2016之前对伦敦自治市镇的名称进行排序。

用户可以在UI中选择y变量。如果我更改代码以包含输入变量（input $ y-从上面的代码中可能是MYE2016），如下所示：

    x_axis <- reactive({
        as.data.frame <- lpop$Name <- reorder(lpop$Name, input$y, FUN = mean)
      })

我收到以下错误：

参数必须具有相同的长度

为什么会出现此错误？

完整代码在这里：

library(shiny) 
library(readxl) # to load the data into R
library(tidyr) # to restructure the data
library(ggplot2) # for the barchart
library(dplyr) # to group and filter the data
library(stringr)
library(dplyr)
library(DT)
library(tools)
library(tidyverse)
library(forcats)

lpop <-read.csv("londonpopchange.csv", header=TRUE)


# Define UI for application that plots features of movies
ui <- fluidPage(

  # Sidebar layout with a input and output definitions
  sidebarLayout(

    # Inputs
    sidebarPanel(

      # Select variable for y-axis
      selectInput(inputId = "y", 
                  label = "Y-axis:",
                  choices = c("Mid Year 2016" = "MYE2016", 
                              "Births" = "Births"), 
                  selected = "MYE2016"),

      # Select variable for x-axis
      selectInput(inputId = "x", 
                  label = "X-axis:",
                  choices = c("Borough" = "Name"), 
                  selected = "Name")
    ),

    # Output
    mainPanel(
      plotOutput(outputId = "geom_bar")
    )
  )
)

# Define server function required to create the scatterplot
server <- function(input, output) {

  # reactive should update when the y axis variable is changed
  # this reorders borough name, by select y axis variable, using mean
  x_axis <- reactive({
    as.data.frame <- lpop$Name <- reorder(lpop$Name, input$y, FUN = mean)
  })


  # Create the scatterplot object the plotOutput function is expecting
  output$geom_bar <- renderPlot({
    ggplot(data = lpop, aes_string(x = x_axis(), y = input$y)) +
      geom_bar(stat = "identity") +
      theme(axis.text.x = element_text(angle = 90))
  })
}

# Create a Shiny app object
shinyApp(ui = ui, server = server)

可以在这里找到数据集：https://www.dropbox.com/s/apez4tyzdm3qjp8/londonpopchange.csv?dl=0

暂时保持简单

参数必须具有相同的长度

0 个答案: