我试图在我闪亮的网络应用程序中创建一种数据透视表,用户可以在其中选择他们想要相互转换的变量。我发现的问题是,当我尝试将强制转换与“输入$列”一起使用时,我得到以下信息:错误:强制转换公式包含在熔融数据中找不到的变量:输入$列。 input$columns 应该是我的数据集中找到的三个列名称之一,所以我不确定问题可能是什么。我附加了代码的简化版本以尝试隔离问题。
UI
library(shiny)
shinyUI(fluidPage(
titlePanel("Reactivity"),
sidebarLayout(
sidebarPanel(
textInput("caption", "Caption:", "Column Name:"),
selectInput("columns", "Choose a dataset:",
choices = c("Publisher", "Region", "Representative")),
numericInput("obs", "Number of observations to view:", 10)
),
mainPanel(
h3(textOutput("caption")),
verbatimTextOutput("summary"),
dataTableOutput('view')
)
)
))
Server
library(shiny)
library(datasets)
shinyServer(function(input, output) {
datasetInput <- reactive({
switch(input$columns,
"Publisher" = Publisher,
"Region" = Region,
"Representative" = Representative)
})
output$caption <- renderText({
input$caption
})
output$summary <- renderPrint({
dataset <- datasetInput()
summary(dataset)
})
output$view <- renderDataTable({
test <- input$columns
m.book.sales <- melt(book.sales)
cast(m.book.sales, test ~ variable, sum)
})
})
和数据集
> head(book.sales)
Representative Region Month Publisher Subject Sales Margin Quantity
1 Raj S 1997-01-01 SAGE Management 135.0 63.45 9
2 Raj S 1997-01-01 Routledge Statistics 120.0 48.00 6
3 Raj S 1997-01-01 Penguin Economics 54.0 22.68 4
4 Raj S 1997-01-01 Routledge Fiction 234.0 128.70 9
5 Soni S 1997-01-01 Penguin Politics 54.0 22.68 4
6 Soni S 1997-01-01 SAGE Politics 185.4 100.12 12