闪亮的反应功能没有按预期更新

原始问题发布在这里： 闪亮的反应性意外行为 https://stackoverflow.com/questions/27478028/shiny-reactive-unexpected-behavior
该问题被重新发布在这里，试图改进之前在上面提供的链接中发布的原始问题，因为我无法获得任何帮助。

客观的：简而言之，该应用程序的目的是允许用户根据提供给用户的各种输入执行搜索、过滤以及对数据帧中提供的数据进行切片和切块。

作为server函数，一个名为的反应函数index已定义为查找与用户输入相对应的索引。反应函数，index, uses grep and which用于在数据帧中定位相应索引的函数df.

我已经包含了可重现的代码，并尝试在适当的情况下包含注释。

关于代码的进一步解释：
这个问题的标题只是我自己的猜测，它基于以下假设：index是正确的。里面的代码可能存在根本问题index而不是反应性index发挥必然作用。为了测试这一点，作为server函数，我已经包含了一个函数printIndex为了打印结果index以确保其正常工作。

我亲自尝试过打印结果ind.j, ind.c, ind.l,ind.d, ind.s, and ind.all每一个都单独连接到控制台，它们似乎都产生了正确的结果。然而，当我测试结果时ind这并不完全符合我的预期，所以我想知道是否是反应性或代码行有问题。什么是ind打算做的是获取所有查找索引的列表，存储在ind.all，并应用intersect递归地从所有子列表中查找公共元素ind.all.

正如我上面提到的，index函数对于单个过滤器效果很好。但是，当我作为用户输入所有索引的值时，该函数不会按预期更新为正确的索引列表。例如，您可以尝试在“应用程序”中输入“应用程序”Job文本输入，“Gas Drive Global”CompanyselectizeInput，和“卡尔加里”Location同时输入文字并点击Search!。您将看到数据表没有返回任何结果，而这显然对应于数据框的第一行df.

#Load required packages
ListofPackages= c('shiny','ggplot2','scales')
lapply(ListofPackages,require,character.only=TRUE)

#Define the dataframe on which the search will be performed
df <- data.frame(Job=c('Applications Engineer ââ¬â Gas Drive',
                       'Engineer, Operations',
                       'Project Engineer',
                       'Project Engineer (Oil & Gas)',
                       'Project Engineer',
                       'Junior Engineer',
                       'Engineer, Operations',
                       'Research and Development (R&D) Junior Engineer',
                       'JUNIOR QUALITY ENGINEER',
                       'Junior Systems Design and Support Engineer',
                       'Mechanical Engineer Calgary, AB',
                       'Applications Engineer',
                       'Project Engineer',
                       'Pipeline Engineer',
                       'Development Engineer',
                       'Specialist Engineering Finance',
                       'Mechanical Engineer - Sudbury',
                       'Project Cost Analyst (12 month term)',
                       'Project Controls Functional Analyst',
                       'Project Controls Professionals'),
             Company=c('Gas Drive Global',
                       'Agrium Wholesale',
                       'City of Calgary',
                       'Stantec',
                       'Shell',
                       'Canadian National Railway',
                       'Pembina Pipeline Corporation',
                       'Velan Inc.',
                       'G.W. Goudreau Personnel Services Ltd',
                       'Stratified Automotive Controls',
                       'Pason Systems Corp.',
                       'Howden',
                       'Plains Midstream Canada',
                       'Amec Foster Wheeler',
                       'Red Bend Software',
                       'Canadian Pacific',
                       'GENIVAR',
                       'Thales',
                       'AltaGas Ltd.','BEMAC Construction Corp.'),
            Location=c('Calgary',
                      'Redwater',
                      'Calgary',
                      'Edmonton',
                      'Sarnia',
                      'Montréal',
                      'Calgary',
                      'Montréal',
                      'Windsor',
                      'Vancouver',
                      'Calgary',
                      'Winnipeg',
                      'Calgary',
                      'Calgary',
                      'Engineer',
                      'Calgary',
                      'Greater Sudbury',
                      'Ottawa',
                      'Calgary',
                      'Calgary'),
              Posted=c(1,
                       1,
                       1,
                       2,
                       2,
                       1,
                       4,
                       5,
                       6,
                       4,
                       1,
                       5,
                       5,
                       3,
                       1,
                       1,
                       15,
                       1,
                       1,
                       13),
             Source=c('Indeed',
                      'Indeed',
                      'Indeed',
                      'Indeed',
                      'Indeed',
                      'Indeed',
                      'Indeed',
                      'Indeed',
                      'Indeed',
                      'Indeed',
                      'Indeed',
                      'Indeed',
                      'Indeed',
                      'Indeed',
                      'Indeed',
                      'Indeed',
                      'Indeed',
                      'Indeed',
                      'Indeed',
                      'Indeed'),
                url=c('http://ca.indeed.com/rc/clk?jk=2371e16aab902f84',
                      'http://ca.indeed.com/rc/clk?jk=428facb738edd397',
                      'http://ca.indeed.com/rc/clk?jk=e15d8fe4d362279b',
                      'http://ca.indeed.com/rc/clk?jk=28c1464fd4e28b24',
                      'http://ca.indeed.com/rc/clk?jk=736ec57bf6902b93',
                      'http://ca.indeed.com/rc/clk?jk=bdc9999eae922645',
                      'http://ca.indeed.com/rc/clk?jk=3a4588fca0e600b1',
                      'http://ca.indeed.com/rc/clk?jk=71f1abcd100850c6',
                      'http://ca.indeed.com/cmp/G.W.Goudreau-Personnel-Services-Ltd/jobs/Junior-Quality-Engineer-3237601a1f3d3abc?r=1',
                      'http://ca.indeed.com/cmp/Stratified-Automotive-Controls/jobs/Junior-System-Design-Support-Engineer-1d916a435e69b8ce?r=1',
                      'http://ca.indeed.com/rc/clk?jk=fca9a784a37ece8a',
                      'http://ca.indeed.com/rc/clk?jk=b2d0975c638c03a8',
                      'http://ca.indeed.com/rc/clk?jk=c92725272c5f9ced',
                      'http://ca.indeed.com/rc/clk?jk=cd97c050df64787c',
                      'http://ca.indeed.com/rc/clk?jk=e6e278ed52532f73',
                      'http://ca.indeed.com/rc/clk?jk=a1f14d52c7798d7b',
                      'http://ca.indeed.com/rc/clk?jk=112350d5e020241f',
                      'http://ca.indeed.com/rc/clk?jk=a324c2dcade7dc5c',
                      'http://ca.indeed.com/rc/clk?jk=77895efdf28ad6fa',
                      'http://ca.indeed.com/cmp/BEMAC-Construction-Corp./jobs/Project-Control-Professional-90796e764f064a51?r=1'))

server <- function(input,output,session){

    #Server-side search for the choices argument of selectizeInput in ui.R
    updateSelectizeInput(session, 'c', choices = as.character(df$Company), server = TRUE)

    #Create a reactive function to look up the indices correponding to the user's inputs
    index <- reactive({
        ind.j <- if(input$j=='') NULL else grep(input$j,df[,'Job'],ignore.case = T)
        ind.c <- {tmp<-lapply(input$c, function(x) {which(df[,'Company']==x)}); Reduce(union,tmp)}
        ind.l <- if(input$l=='') NULL else grep(input$l,df[,'Location'],ignore.case = T)
        ind.d <- which(df[,'Posted']<=input$d)
        ind.s <- {tmp<-lapply(input$s, function(x) {which(df[,'Source']==x)}); Reduce(union,tmp)}
        ind.all <- list(ind.j,ind.c,ind.l,ind.d,ind.s)
        ind <- if(is.null(ind.s)) NULL else {ind.null<- which(lapply(ind.all,is.null)==TRUE) ;Reduce(intersect,ind.all[-ind.null])}

    })

    #Create a reactive function to return the search results by returning the indices looked up in the index function above
    search <- reactive({

              df[index(),]

    })

    #Print the results of the index function above to test if it works properly
    output$printIndex <- renderUI({
           list(index())
    })

    #Send the searchresult table to ui.R to print the results of the search function above
    output$searchresult <- renderDataTable({
        input$action6   #triggered only when button is pressed
        if(input$action6==0) return() 
        else{isolate({
            transformed <- transform(search(), Link = paste('<a href = ', shQuote(url), '>', 'Click</a>'))
            transformed <- transformed[,c(1:3,5,7,4,6)] #Rearrange columns
            transformed[-7] #Remove last column
        })
        }
    }, option=list(autoWidth=FALSE,pageLength=100,
                   columnDefs = list(list(targets =c(5,6) -1, searchable = FALSE),list(sWidth=c("100px")))))


}

ui <- shinyUI(fluidPage(

    #Display datatable filters on top
    tags$head(tags$style("tfoot {display: table-header-group;}")),        

    #Add a title
    h1('Power Search'),

    #Use the Sidebar layout
    sidebarLayout(
        sidebarPanel(

            #Add various fields for the user in order to search the dataframe  
                     h5('Note: Running the app takes a little while at startup.'),
                     helpText('Job:'),
                     textInput('j',''),
                     helpText('Company:'),
                     selectizeInput('c','',choices=NULL,multiple=T),
                     helpText('Location:'),
                     textInput('l',''),
                     sliderInput('d','Posted (days ago)',min = 0,max = 60,step = 5,value = 60),
                     checkboxGroupInput('s','',choices = c('Indeed','Glassdoor'),selected = c('Indeed','Glassdoor')),
                     actionButton('action6','Search!')
        ),


        mainPanel(

            #Display results
            htmlOutput('printIndex'),
            dataTableOutput('searchresult')
        )      

    )
))

shinyApp(ui = ui, server = server)

你遇到的问题是which功能：

> which(rep(FALSE, 5))
integer(0)

你可以改变：

ind <- if(is.null(ind.s)){
  NULL
}else{
  ind.null<- which(lapply(ind.all,is.null)==TRUE)
  Reduce(intersect,ind.all[-ind.null])
}

to

ind <- if(is.null(ind.s)){
  NULL
}else{
  Reduce(intersect,ind.all[!sapply(ind.all,is.null)])
}