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51 lines
1.6 KiB
R
51 lines
1.6 KiB
R
library(shiny)
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library(datasets)
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shinyServer(function(input, output) {
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# By declaring databaseInput as a reactive function we ensure that:
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#
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# 1) It is only called when the inputs it depends on changes
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# 2) The computation and result are shared by all the callers (it
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# only executes a single time)
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#
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datasetInput <- reactive(function() {
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switch(input$dataset,
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"rock" = rock,
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"pressure" = pressure,
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"cars" = cars)
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})
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# The output$caption is computed based on a reactive function that
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# returns input$caption. When the user changes the "caption" field:
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#
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# 1) This function is automatically called to recompute the output
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# 2) The new caption is pushed back to the browser for re-display
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#
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# Note that because the data-oriented reactive functions below don't
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# depend on input$caption, those functions are NOT called when the
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# input$caption changes.
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#
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output$caption <- reactive(function() {
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input$caption
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})
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# The output$summary depends on the datasetInput reactive function,
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# so will be re-executed whenever datasetInput is re-executed
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# (i.e. whenever the input$dataset changes)
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#
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output$summary <- reactiveText(function() {
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dataset <- datasetInput()
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summary(dataset)
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})
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# The output$view depends on both the databaseInput reactive function,
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# and input$obs, so will be re-executed whenever input$dataset or
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# input$obs is changed.
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#
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output$view <- reactiveTable(function() {
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obs <- as.integer(input$obs)
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head(datasetInput(), n = obs)
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})
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})
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