如何在R中交互编辑矢量

Question

我想在R中创建一个矢量，添加元素并在ui.R中显示结果。

但似乎在server.R中，它会覆盖向量中的旧元素，而不是附加向量。

这里是我的代码

ui.R

shinyUI(pageWithSidebar(
    headerPanel("actionButton test"), 
    sidebarPanel(
    textInput("symb", "Symbol", "SPY"), 
    br(), 
    actionButton("addButton", "Add"), 
    p("Click the button to update the value displayed in the main panel.") 
), 
    mainPanel(
    verbatimTextOutput("nText") 
) 
)) 

server.R

equity_list = c("ACN") 
shinyServer(function(input, output) { 
    output$nText <- renderText({ 
    # Take a dependency on input$goButton 
    input$goButton 

    # Use isolate() to avoid dependency on input$n 
    isolate(input$symb) 

    equit_list <<- append(equity_list, input$symb) 
    }) 
}) 

Answer 1

嗨，你在你的应用程序两个问题：

1. 你做不使用的正确编号在server.R

2. 你必须覆盖equity_list当你添加一个新的元素

试试这个：

library(shiny) 
runApp(list(
    ui = pageWithSidebar(
    headerPanel("actionButton test"), 
    sidebarPanel(
     textInput("symb", "Symbol", "SPY"), 
     br(), 
     actionButton("addButton", "Add"), 
     p("Click the button to update the value displayed in the main panel.") 
    ), 
    mainPanel(
     verbatimTextOutput("nText") 
    ) 
), 
    server = function(input, output) { 
    equity_list = c("ACN") 
    output$nText <- renderText({ 
     input$addButton 
     isolate({ 
     equity_list <<- append(equity_list, input$symb) 
     }) 
    }) 
    } 
)) 

编辑：2个按钮，这并不容易。你可以尝试下面的应用程序，这是你必须在“删除”之后添加“添加”。我已经改变了textInput为selectizeInput，它更灵活：

library(shiny) 
runApp(list(
    ui = pageWithSidebar(
    headerPanel("actionButton test"), 
    sidebarPanel(
     selectizeInput(inputId = "symb", label = "Symbol", selected = "SPY", choices = "SPY", multiple = TRUE, options = list(create = TRUE)), 
     br(), 
     actionButton("addButton", "Add"), 
     p("Click the button to update the value displayed in the main panel."), 
     actionButton("deleteButton", "Delete") 
    ), 
    mainPanel(
     verbatimTextOutput("nText") 
    ) 
), 
    server = function(input, output, session) { 
    equity_list = c("ACN") 

    equity_rea <- reactive({ 
     equity_list <- append(equity_list, input$symb) 
    }) 

observe({ 
    input$deleteButton 
    updateSelectizeInput(session = session, inputId = "symb", selected = "SPY") 
}) 

output$nText <- renderText({ 
    # with add button 
    input$addButton | input$deleteButton 
    isolate(equity_rea()) 
    # without add button 
    #equity_rea() 
}) 

} ））