googleVis中的闪亮导致数据集具有不同的行数

Question

我正在尝试使用Shiny来创建googleVis气泡图。在Shiny服务器之外，这段代码工作正常：

df=data.frame(states=gun_stats$new_states, household=gun_stats$Gun.Ownership..2007., murder=gun_stats$Gun.Murder.Rate.per.100K..2010.,
          attack_size=gun_stats$state_attacks,attack_size_group=gun_stats$attack_category,
          gun_stats$x)


Bubble <- gvisBubbleChart(df, idvar="states", xvar="household", yvar="murder",colorvar="attack_size", sizevar="attack_size",
                      options=list(hAxis="{title:'% Housholds with Guns'}",
                                   vAxis="{title: 'Gun muder rate per 100k'}",height="600"))
plot(Bubble)

然后我尝试按照以下方式将其放入Shiny应用程序中：

server.R

shinyServer(function(input, output, session) {

    df=data.frame(states=gun_stats$new_states, household=gun_stats$Gun.Ownership..2007., murder=gun_stats$Gun.Murder.Rate.per.100K..2010.,
              attack_size=gun_stats$state_attacks, attack_size_group=gun_stats$attack_category)    

    output$chart <- renderGvis({
    gvisBubbleChart(df, idvar="states", xvar="household", yvar="murder",colorvar="attack_var", sizevar="attack_var",
                    options=list(hAxis="{title:'% Housholds with Guns'}",
                                 vAxis="{title: 'Gun muder rate per 100k'}",height="600"))
    })   
})

ui.R

library(googleVis)
library(shiny)
pageWithSidebar(
headerPanel("Mass Shootings Overview"),
     sidebarPanel(
        selectInput("attack_var", "Choose a size metric", 
                    choices = c("x", "attack_size"))
    ),
mainPanel(htmlOutput('chart'))
)

然而，这会返回：data.frame中的错误：参数意味着不同的行数：51,0

有什么建议吗？