R 我自己绘制柱状图的函数没有'；我不能在光亮的地方工作

我已经编写了一个函数，它在一个简单的脚本中可以完美地工作，但在shiny中却不能。此函数用于创建直方图

如果我尝试在没有光泽的情况下绘制柱状图，它会起作用

val <- c(2.1490626,3.7928443,2.2035281,1.5927854,3.1399245,2.3967338,3.7915825,4.6691277,3.0727319,2.9230937,2.6239759,3.7664386,4.0160378,1.2500835,4.7648343,0.0000000,5.6740227,2.7510256,3.0709322,2.7998003,4.0809085,2.5178086,5.9713330,2.7779843,3.6724801,4.2648527,3.6841084,2.5597235,3.8477471,2.6587736,2.2742209,4.5862788,6.1989269,4.1167091,3.1769325,4.2404515,5.3627032,4.1576810,4.3387921,1.4024381,0.0000000,4.3999099,3.4381837,4.8269218,2.6308474,5.3481382,4.9549753,4.5389650,1.3002293,2.8648220,2.4015338,2.0962332,2.6774765,3.0581759,2.5786137,5.0539080,3.8545796,4.3429043,4.2233248,2.0434363,4.5980727)
df1 <- data.frame(val)
df1$type <- "Type 1"
val <- c(3.7691229,3.6478055,0.5435826,1.9665861,3.0802654,1.2248374,1.7311236,2.2492826,2.2365337,1.5726119,2.0147144,2.3550348,1.9527204,3.3689502,1.7847986,3.5901329,1.6833872,3.4240479,1.8372175,0.0000000,2.5701453,3.6551315,4.0327091,3.8781182)
df2 <- data.frame(val)
df2$type <- "Type 2"
df3 <- rbind(df1, df2)
bins = 10
min = NULL
max = NULL

histogram_function <- function(data, bins, min, max){
  hist <- ggplot(data, aes(val, fill=type)) +
    geom_histogram(position = "identity", colour = "grey40", bins = bins) +
    ggtitle("Here must be a title") +
    xlab("Values") +
    ylab("Frequency") +
    facet_grid(type ~ .)  
  return(hist)
}

histogram_function(data=df3, bins=bins, min=min, max=max)

---

val您使用
sidebarLayout
来定义
sidebarPanel
和
mainPanel
。在您的示例中，您没有定义导致错误的
侧边栏面板
。您可以使用空的
侧边栏面板
，也可以只使用
fluidPage

更改
用户界面
，则它可以工作：

ui <- fluidPage(
  
  # Application title
  titlePanel("My shiny app"),
  
  sidebarLayout(
    sidebarPanel(),
    mainPanel(
      plotOutput("histogram")
    )
  )
)

ui
ui <- fluidPage(
  
  # Application title
  titlePanel("My shiny app"),
  
  sidebarLayout(
    sidebarPanel(),
    mainPanel(
      plotOutput("histogram")
    )
  )
)