Shiny 应用程序失败，“参数 1(类型 'closure')无法由 'cat' 处理"- 这是什么意思? [英] Shiny app fails with "argument 1 (type 'closure') cannot be handled by 'cat'" - what does this mean?

问题描述

我正在构建一个 Shiny 应用程序，它接受用户的文本输入，将最后两个单词与三元组数据框进行比较，以预测最有可能的下一个单词.在 server.R 中，我试图输出的 triPred 函数的输出是一个单词.当我加载这个应用程序时，我在应用程序中输入一些文本后收到以下错误 - 参数 1(类型 'closure')不能由 'cat' 处理 - 这似乎与 server.R 中的最后一行有关这只是一个词，我不清楚猫"即连接有什么问题.

I am building a Shiny app that takes a user's text input, compares the last two words to a data frame of trigrams to predict the most likely next word. In server.R below the output of the triPred function which I am trying to ouptut is a single word. When I load this app I get the following error after I type some text into the app - 'argument 1 (type 'closure') cannot be handled by 'cat' - which appears to be related to the final line in server.R As this is just a single word, I am unclear what is failing with 'cat' ie concatenate.

server.R

library(stringr)

shinyServer(function(input, output) {

    triSplit <- function(input) {
            el <- unlist(str_split(input," "))
            bigram <- paste(el[length(el)-1],el[length(el)])
            return(bigram)
    }

    triPred <- function(input) {
            ## pulls out end words that match the input bigram
            temp_wf_T <- wf_T[wf_T$start == triSplit(input),]
            ##Picks one of the best options at random based on count
            ans <- sample(temp_wf_T$end[temp_wf_T$count == max(temp_wf_T$count)],1)
            return(ans) }

    ##Read in a dataframe of bigrams, their possible completions, and counts of occurence
    wf_T<-readRDS("C:/Users/LTM/DataScienceCertificateCapstone/ShinyTest/data/tdm.rds")
    ##Runs the triPred function to guess the next most likely word
    ans <- reactive(triPred(input$sent))
    ##generates an output variable to display
    output$out <- renderText({ans})
    })

ui.R

library(shiny)

shinyUI(fluidPage(
    titlePanel(h1("My Shiny App", align = "center")),
    sidebarLayout(
            sidebarPanel(helpText("Please enter a sentence you would like me to complete"),
            textInput("sent", label = "sentence")),
            ##########
            mainPanel(h1("Best Guess"),
            br(),
            textOutput("out")
            )
    )
))

推荐答案

很难说，因为我无法重现您的应用程序，但您应该尝试:

It's hard to tell since I can't reproduce your app, but you should try with:

output$out <- renderText({ans()}) 或者只是 output$out <- renderText(ans()).

如果你省略了 ()，你访问的是响应式本身，而不是它的值.有点像为函数键入 foo 而不是 foo().

If you omit the (), you access the reactive itself, and not the value of it. A bit like when you type foo instead of foo() for a function.

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