我想创建一个“selectInput”小部件，其值的选择是“fileInput”小部件导入的数据集中列的名称。
我尝试“tableOutput”数据集的名称，作为“selectInput”小部件的“choices”参数的参数，但它不起作用。我在小部件中获得的唯一选择是“name”，“id”和“class”。
这是我使用的代码：
library(shiny)
ui <- fluidPage(
# Widget for loading data set
fileInput("file", label = h4("Input csv data set")),
# Widget for selecting the variable among names of columns of the data set
selectInput("select.variable", label = h4("Select variable from data set"),
choices = tableOutput("list.var"), selected = 1) # This approach doesn't work
)
server <- function(input, output) {
# The goal was to get the list of names of columns to use it as "choices"
# in the "selectInput" widget
output$list.var <- renderTable({
inFile <- input$file
if (is.null(inFile)) # To avoid error messages when the file is not yet loaded
return(NULL)
# After the file is loaded
data.fr <- read.csv(inFile$datapath)
list.var <- names(data.fr[1,]) # Get the names of the columns of the dataset
})
}
shinyApp(ui = ui, server = server)
有没有办法使用导入数据集的列名作为“selectInput”小部件的选项？
答案 0 :(得分：0)
这样的事情应该可以解决问题。我使用renderUI从数据集
library(shiny)
ui <- fluidPage(
# Widget for loading data set
fileInput("file", label = h4("Input csv data set")),
uiOutput("myslider")
)
server <- function(input, output) {
# The goal was to get the list of names of columns to use it as "choices"
# in the "selectInput" widget
output$myslider <- renderUI({
# Widget for selecting the variable among names of columns of the data set
selectInput("select.variable", label = h4("Select variable from data set"),
choices = names(mydata()), selected = 1) # This approach doesn't work
})
mydata <- reactive({
inFile <- input$file
if (is.null(inFile)) # To avoid error messages when the file is not yet loaded
return(NULL)
# After the file is loaded
data.fr <- read.csv(inFile$datapath)
names(data.fr[1,]) # Get the names of the columns of the dataset
})
output$list.var <- renderTable({
mydata()
})
}
shinyApp(ui = ui, server = server)