[英]isolate conditionalPanel in shiny
我有一个shiny
标签,用户可以在其中通过selectInput
选择多个参数。 选择之后,用户单击一个actionButton
,服务器端将进行大量计算。 根据结果和选择,应该显示一个或几个conditionalPanels
。 问题在于,一旦用户更改了选择,显示的conditionalPanel
就会立即更改。 但是,我希望仅在用户再次按下actionButton
并更新服务器端的计算之后才能评估条件。 有没有办法将conditionalPanel的conditionalPanel
绑定到actionButton
?
这是我能想到的最好的MWE,可以捕获所有细微差别(实际上,这里仍然缺少条件面板对某些服务器结果的依赖性):
library(shiny)
library(plyr)
ui <- fluidPage(
selectInput("variable", "Variable:",
c("SLength" = "Sepal.Length",
"SWidth" = "Sepal.Width",
"PLength" = "Petal.Length",
"PWidth" = "Petal.Width",
"Species" = "Species"),
multiple = TRUE),
br(),
actionButton("goButton", "Go!"),
hr(),
conditionalPanel(condition = "input['variable'].length == 1",
plotOutput("oneplot")),
conditionalPanel(condition = "input['variable'].length == 2",
plotOutput("twoplot"))
)
server <- function(input, output){
v <- reactiveValues(plot.type = NULL)
observeEvent(input$goButton, {
if (is.null(input$variable)) return(NULL)
if ("Species" %in% input$variable & length(input$variable > 1)){
sec.var <- input$variable[which(input$variable != "Species")]
v$summary <- ldply(by(iris[,sec.var], iris$Species, mean))
v$summary[,1] <- as.factor(v$summary[,1])
} else if ("Species" %in% input$variable)
v$summary <- table(iris$Species) else
v$summary <- iris[,input$variable]
})
output$oneplot <- renderPlot({
if (is.null(v$summary)) return(NULL)
if (input$variable == "Species") return(NULL)
hist(v$summary)
})
output$twoplot <- renderPlot({
if (is.null(v$summary)) return(NULL)
plot(v$summary)
})
}
shinyApp(ui, server)
假设我启动了该应用程序,然后选择SLength
和SWidth
,单击Go
-Button并得到一个点图。 然后,我想显示SLength
vs. PLength
,所以我从选择字段中删除了SWidth
,同时获得了两个直方图,每个先前的选择一个。 条件面板会立即对input$variable
的更改作出反应,而服务器脚本中的观察者仍在等待我按下按钮。 显然,这不是用户期望的行为。 预期的行为是对条件面板条件的评估仅在按下“ Go
按钮时进行。 有没有办法做到这一点?
在服务器端做条件怎么样?
library(shiny)
library(plyr)
ui <- fluidPage(
selectInput("variable", "Variable:",
c("SLength" = "Sepal.Length",
"SWidth" = "Sepal.Width",
"PLength" = "Petal.Length",
"PWidth" = "Petal.Width",
"Species" = "Species"),
multiple = TRUE),
br(),
actionButton("goButton", "Go!"),
hr(),
plotOutput("oneplot")
# conditionalPanel(condition = "input['variable'].length == 1",
# plotOutput("oneplot")),
# conditionalPanel(condition = "input['variable'].length == 2",
# plotOutput("twoplot"))
)
server <- function(input, output){
v <- reactiveValues(plot.type = NULL)
observeEvent(input$goButton, {
if (is.null(input$variable)) return(NULL)
if ("Species" %in% input$variable & length(input$variable > 1)){
sec.var <- input$variable[which(input$variable != "Species")]
v$summary <- ldply(by(iris[,sec.var], iris$Species, mean))
v$summary[,1] <- as.factor(v$summary[,1])
} else if ("Species" %in% input$variable)
v$summary <- table(iris$Species) else
v$summary <- iris[,input$variable]
})
output$oneplot <- renderPlot({
#Added actionButton dependency here
input$goButton
isolate({
if(length(input$variable)== 1) {
if (is.null(v$summary)) return(NULL)
if (input$variable == "Species") return(NULL)
hist(v$summary)
}
else {
if (is.null(v$summary)) return(NULL)
plot(v$summary)
}
})
})
#output$twoplot <- renderPlot({
#if (is.null(v$summary)) return(NULL)
#plot(v$summary)
#})
}
shinyApp(ui, server)
编辑:通过使用submitButton添加了另一个选项
您还可以使用submitButton()
,并将observeEvent()
附加到input$variable()
。 “包含输入按钮的表单不会在输入发生更改时自动更新其输出,而是会等到用户显式单击提交按钮之后。” 提交按钮
library(shiny)
library(plyr)
ui <- fluidPage(
selectInput("variable", "Variable:",
c("SLength" = "Sepal.Length",
"SWidth" = "Sepal.Width",
"PLength" = "Petal.Length",
"PWidth" = "Petal.Width",
"Species" = "Species"),
multiple = TRUE),
br(),
submitButton("Go!"),
hr(),
conditionalPanel(condition = "input['variable'].length == 1",
plotOutput("oneplot")),
conditionalPanel(condition = "input['variable'].length == 2",
plotOutput("twoplot"))
)
server <- function(input, output){
v <- reactiveValues(plot.type = NULL)
observeEvent(input$variable, {
if (is.null(input$variable)) return(NULL)
if ("Species" %in% input$variable & length(input$variable > 1)){
sec.var <- input$variable[which(input$variable != "Species")]
v$summary <- ldply(by(iris[,sec.var], iris$Species, mean))
v$summary[,1] <- as.factor(v$summary[,1])
} else if ("Species" %in% input$variable)
v$summary <- table(iris$Species) else
v$summary <- iris[,input$variable]
})
output$oneplot <- renderPlot({
if (is.null(v$summary)) return(NULL)
if (input$variable == "Species") return(NULL)
hist(v$summary)
})
output$twoplot <- renderPlot({
if (is.null(v$summary)) return(NULL)
plot(v$summary)
})
}
shinyApp(ui, server)
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