您可以使用reactiveTimer
要做到这一点。我修改了您代码的服务器部分。在下面的代码中,我将计时器设置为两秒,以便绘图每两秒更新一次。
server <- function(input, output) {
autoInvalidate <- reactiveTimer(2000)
plot1 <- NULL
output$plot1 <- renderPlot({
plot1 <<- ggplot(data, aes(x=x, y=y)) + geom_point(colour="red") + theme_bw()
plot1 <<- plot1 + geom_vline(xintercept = mean(data$x), size=1.1, colour="red")
plot1
})
observeEvent(input$button,{
output$plot1 <- renderPlot({
autoInvalidate()
data$sampled <- "red"
sample.rows <- sample(data$ID, 20, replace = F)
data$sampled[sample.rows] <- "green"
plot1 <<- plot1 + geom_point(x=data$x, y=data$y, colour=data$sampled, size=2)
sample.mean.x <- mean(data$x[sample.rows])
plot1 <<- plot1 + geom_vline(xintercept = sample.mean.x, colour="green")
plot1
})
})
}
[EDIT]:
由于您希望循环只运行 20 次,我在答案的帮助下修改了代码this https://stackoverflow.com/a/43251477/5894457链接,以便反应式计时器仅运行到计数为 20 为止。以下是您需要从链接添加的代码:
invalidateLaterNew <- function (millis, session = getDefaultReactiveDomain(), update = TRUE)
{
if(update){
ctx <- shiny:::.getReactiveEnvironment()$currentContext()
shiny:::timerCallbacks$schedule(millis, function() {
if (!is.null(session) && session$isClosed()) {
return(invisible())
}
ctx$invalidate()
})
invisible()
}
}
unlockBinding("invalidateLater", as.environment("package:shiny"))
assign("invalidateLater", invalidateLaterNew, "package:shiny")
这是它的服务器代码:
server <- function(input, output, session) {
count = 0
plot1 <- NULL
output$plot1 <- renderPlot({
plot1 <<- ggplot(data, aes(x=x, y=y)) + geom_point(colour="red") + theme_bw()
plot1 <<- plot1 + geom_vline(xintercept = mean(data$x), size=1.1, colour="red")
plot1
})
observeEvent(input$button,{
count <<- 0
output$plot1 <- renderPlot({
count <<- count+1
invalidateLater(1500, session, count < 20)
data$sampled <- "red"
sample.rows <- sample(data$ID, 20, replace = F)
data$sampled[sample.rows] <- "green"
plot1 <<- plot1 + geom_point(x=data$x, y=data$y, colour=data$sampled, size=2)
sample.mean.x <- mean(data$x[sample.rows])
plot1 <<- plot1 + geom_vline(xintercept = sample.mean.x, colour="green")
plot1
})
})
}