R Shiny-第一个块中的数据集加载在第二个块中不存在...? [英] R Shiny - dataset load in a first chunk doesn't exist in a second chunk ...?

问题描述

我使用库 learnr 构建的闪亮应用程序中出现一个奇怪的错误.关于我刚刚加载并可视化的对象的错误"找不到对象"(表示该对象不存在?)

I have a strange error in a shiny app I built with the library learnr. An error "Object not found" about an object I just loaded and just visualized (meaning the object exists no ?)

尽管我没有可复制的示例，但有些人可能会理解是什么导致了错误:

Although I don't have a reproducible example, some of you will maybe understand what is creating the error :

• 我有第一个块{r load}，它加载数据集.这里没有错误，我什至可以可视化数据集(下面的屏幕截图)

• I have a first chunk {r load} that loads a dataset. There is no error here, I can even visualize the dataset (screenshot below)

然后我有第二块，我想在那儿操纵数据集.但这告诉我数据集不存在！怎么可能，我只是将它可视化了一个? ...

Then I have a second chunk, where I would like to manipulate the dataset. But it tells me dataset doesn't exist ! How it could be possible, I just visualized it one chunk before ?! ...

我不明白一个数据集如何存在于一个块中，而不是另一个中.这是否意味着数据集未加载到全局环境中?学习者库有问题吗?

I don't understand how a dataset could be exists in a chunk, and not in another. Does it mean the dataset isn't loaded in the global environment ? Is it a problem with the learnr library ?

也许有人会有想法，或者我可以测试的东西.预先谢谢你.

Maybe someone will have an idea, or something I could test. Thank you in advance.

问题在于环境/工作空间.在第一个块中，即使我加载数据集，也不会将其存储在环境中.我在第二个块中测试了功能ls()，它告诉我工作空间中没有对象.加载的数据集不在这里，我不知道为什么...

The problem is about the environment/workspace. In the first chunk, even if I load the dataset, it is not store in the environment. I tested the function ls() in a second chunk, and it tells me there is no object in the workspace. The loaded dataset is not here, I don't know why ...

推荐答案

在我看来，Shiny不存储任何数据.您必须按照以下说明将其手动从一个块传递到另一块(仅添加server中的代码段):

In my opinion, shiny doesn't store any data. You have to pass it manually from one chunk to other as follow (only adding the code snippet from server):

server <- function(input, output, session) {
  output$heat <- renderPlotly({
    Name<-c("John","Bob","Jack")
    Number<-c(3,3,5)
    Count<-c(2,2,1)
    NN<-data.frame(Name,Number,Count)
    render_value(NN) # You need function otherwise data.frame NN is not visible
    # You can consider this as chunk 1
  })

  render_value=function(NN){
   # Here your loaded data is available
     head(NN)
   # You can consider this as chunk 2 
    })  
  }           
}

shinyApp(ui, server)

您可以在此处找到完整的代码:子集a基于可点击事件的数据框

You can find full code here: Subset a dataframe based on plotly click event

OR

按照此处的建议创建global.R文件并遵循以下URL:

Create global.R file as suggested here and follow this URL: R Shiny - create global data frame at start of app

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