r - 使用 Shiny 的文本输入和 dplyr 来过滤数据框中的行

Question

我正在尝试使用 Shiny 应用程序上的文本输入小部件来过滤数据框中的行，但我无法使其正常工作。

数据集

df1<-data.frame (Name=c("Carlos","Pete","Carlos","Carlos","Carlos","Pete","Pete","Pete","Pete","Homer"),Sales=(as.integer(c("3","4","7","6","4","9","1","2","1","9"))))

用户界面

shinyUI(fluidPage(
titlePanel("Sales trends"),titlePanel("People score"),

sidebarLayout(sidebarPanel(

  textInput("text", label = h3("Text input"), value = "Enter text..."),

  numericInput("obs", "Number of observations to view:", 3),

  helpText("Note: while the data view will show only the specified",
           "number of observations, the summary will still be based",
           "on the full dataset."),

  submitButton("Update View")
),

mainPanel(
  h4("Volume: Total sales"),
  verbatimTextOutput("volume"),

  h4("Top people"),
  tableOutput("view")
))))

服务器

library(shiny)
library (dplyr)
df1<-data.frame (Name=c("Carlos","Pete","Carlos","Carlos","Carlos","Pete","Pete","Pete","Pete","Homer"),Sales=(as.integer(c("3","4","7","6","4","9","1","2","1","9"))))
shinyServer(function(input, output) {
output$value <- renderPrint({ input$text })
datasetInput <- reactive({
switch(input$dataset,df1%>% filter(Name %in% "input$text")%>% select(Name, Sales)%>% arrange(desc(Sales)))
})
output$volume <- renderPrint({
dataset <- datasetInput()
sum(dataset$Sales)
})})

Answer 1

正如 aosmith 指出的那样，您需要删除引号以进行过滤。其次，您应该在 filter() 中使用 == 而不是 %in%。第三，在其他情况下您会使用 switch()(阅读 ?switch)，但在这里您不需要它。

您的 server.R 应该如下所示:

library(shiny)
library(dplyr)
df1 <- data_frame(Name = c("Carlos","Pete","Carlos","Carlos","Carlos","Pete",
                         "Pete","Pete","Pete","Homer"),
                  Sales = c(3, 4, 7, 6, 4, 9, 1, 2, 1, 9))

shinyServer(function(input, output) {
  datasetInput <- reactive({
    df1 %>% filter(Name == input$text) %>% arrange(desc(Sales))
  })
  output$volume <- renderPrint({
    dataset <- datasetInput()
    dataset$Sales
  })
})