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2024-12-17
In this exercise, we will delve into the capabilities of the shiny package, build a simple Shiny application, and enhance its features with customized input and output components. The shiny package is an essential tool in R that allows users to create dynamic and interactive web-based applications seamlessly within the R environment.
# Install shiny (if not already installed)
if (!requireNamespace("shiny", quietly = TRUE)) {
install.packages("shiny")
}
library(shiny)## Warning: package 'shiny' was built under R version 4.3.3## starting httpd help server ... done## [1] "a" "absolutePanel"
## [3] "actionButton" "actionLink"
## [5] "addResourcePath" "animationOptions"
## [7] "appendTab" "as.shiny.appobj"
## [9] "basicPage" "bindCache"
## [11] "bindEvent" "bookmarkButton"
## [13] "bootstrapLib" "bootstrapPage"
## [15] "br" "browserViewer"
## [17] "brushedPoints" "brushOpts"
## [19] "busyIndicatorOptions" "callModule"
## [21] "captureStackTraces" "checkboxGroupInput"
## [23] "checkboxInput" "clickOpts"
## [25] "code" "column"
## [27] "conditionalPanel" "conditionStackTrace"
## [29] "conditionStackTrace<-" "createRenderFunction"
## [31] "createWebDependency" "dataTableOutput"
## [33] "dateInput" "dateRangeInput"
## [35] "dblclickOpts" "debounce"
## [37] "devmode" "dialogViewer"
## [39] "diskCache" "div"
## [41] "downloadButton" "downloadHandler"
## [43] "downloadLink" "em"
## [45] "enableBookmarking" "eventReactive"
## [47] "exportTestValues" "exprToFunction"
## [49] "ExtendedTask" "fileInput"
## [51] "fillCol" "fillPage"
## [53] "fillRow" "fixedPage"
## [55] "fixedPanel" "fixedRow"
## [57] "flowLayout" "fluidPage"
## [59] "fluidRow" "freezeReactiveVal"
## [61] "freezeReactiveValue" "get_devmode_option"
## [63] "getCurrentOutputInfo" "getCurrentTheme"
## [65] "getDefaultReactiveDomain" "getQueryString"
## [67] "getShinyOption" "getUrlHash"
## [69] "h1" "h2"
## [71] "h3" "h4"
## [73] "h5" "h6"
## [75] "headerPanel" "helpText"
## [77] "hideTab" "hoverOpts"
## [79] "hr" "HTML"
## [81] "htmlOutput" "htmlTemplate"
## [83] "httpResponse" "icon"
## [85] "imageOutput" "img"
## [87] "in_devmode" "includeCSS"
## [89] "includeHTML" "includeMarkdown"
## [91] "includeScript" "includeText"
## [93] "incProgress" "inputPanel"
## [95] "insertTab" "insertUI"
## [97] "installExprFunction" "invalidateLater"
## [99] "is.key_missing" "is.reactive"
## [101] "is.reactivevalues" "is.shiny.appobj"
## [103] "is.singleton" "isolate"
## [105] "isRunning" "isTruthy"
## [107] "key_missing" "loadSupport"
## [109] "mainPanel" "makeReactiveBinding"
## [111] "markdown" "markRenderFunction"
## [113] "maskReactiveContext" "memoryCache"
## [115] "MockShinySession" "modalButton"
## [117] "modalDialog" "moduleServer"
## [119] "navbarMenu" "navbarPage"
## [121] "navlistPanel" "nearPoints"
## [123] "need" "NS"
## [125] "ns.sep" "numericInput"
## [127] "observe" "observeEvent"
## [129] "onBookmark" "onBookmarked"
## [131] "onFlush" "onFlushed"
## [133] "onReactiveDomainEnded" "onRestore"
## [135] "onRestored" "onSessionEnded"
## [137] "onStop" "onUnhandledError"
## [139] "outputOptions" "p"
## [141] "pageWithSidebar" "paneViewer"
## [143] "parseQueryString" "passwordInput"
## [145] "plotOutput" "plotPNG"
## [147] "pre" "prependTab"
## [149] "printError" "printStackTrace"
## [151] "Progress" "quoToFunction"
## [153] "radioButtons" "reactive"
## [155] "reactiveConsole" "reactiveFileReader"
## [157] "reactivePoll" "reactiveTimer"
## [159] "reactiveVal" "reactiveValues"
## [161] "reactiveValuesToList" "reactlog"
## [163] "reactlogAddMark" "reactlogReset"
## [165] "reactlogShow" "register_devmode_option"
## [167] "registerInputHandler" "registerThemeDependency"
## [169] "removeInputHandler" "removeModal"
## [171] "removeNotification" "removeResourcePath"
## [173] "removeTab" "removeUI"
## [175] "renderCachedPlot" "renderDataTable"
## [177] "renderImage" "renderPlot"
## [179] "renderPrint" "renderTable"
## [181] "renderText" "renderUI"
## [183] "repeatable" "req"
## [185] "resourcePaths" "restoreInput"
## [187] "runApp" "runExample"
## [189] "runGadget" "runGist"
## [191] "runGitHub" "runTests"
## [193] "runUrl" "safeError"
## [195] "selectInput" "selectizeInput"
## [197] "serverInfo" "setBookmarkExclude"
## [199] "setProgress" "setSerializer"
## [201] "shinyApp" "shinyAppDir"
## [203] "shinyAppFile" "shinyAppTemplate"
## [205] "shinyOptions" "shinyServer"
## [207] "shinyUI" "showBookmarkUrlModal"
## [209] "showModal" "showNotification"
## [211] "showTab" "sidebarLayout"
## [213] "sidebarPanel" "singleton"
## [215] "sizeGrowthRatio" "sliderInput"
## [217] "snapshotExclude" "snapshotPreprocessInput"
## [219] "snapshotPreprocessOutput" "span"
## [221] "splitLayout" "stopApp"
## [223] "strong" "submitButton"
## [225] "suppressDependencies" "tableOutput"
## [227] "tabPanel" "tabPanelBody"
## [229] "tabsetPanel" "tag"
## [231] "tagAppendAttributes" "tagAppendChild"
## [233] "tagAppendChildren" "tagGetAttribute"
## [235] "tagHasAttribute" "tagList"
## [237] "tags" "tagSetChildren"
## [239] "testServer" "textAreaInput"
## [241] "textInput" "textOutput"
## [243] "throttle" "titlePanel"
## [245] "uiOutput" "updateActionButton"
## [247] "updateActionLink" "updateCheckboxGroupInput"
## [249] "updateCheckboxInput" "updateDateInput"
## [251] "updateDateRangeInput" "updateNavbarPage"
## [253] "updateNavlistPanel" "updateNumericInput"
## [255] "updateQueryString" "updateRadioButtons"
## [257] "updateSelectInput" "updateSelectizeInput"
## [259] "updateSliderInput" "updateTabsetPanel"
## [261] "updateTextAreaInput" "updateTextInput"
## [263] "updateVarSelectInput" "updateVarSelectizeInput"
## [265] "urlModal" "useBusyIndicators"
## [267] "validate" "validateCssUnit"
## [269] "varSelectInput" "varSelectizeInput"
## [271] "verbatimTextOutput" "verticalLayout"
## [273] "wellPanel" "with_devmode"
## [275] "withLogErrors" "withMathJax"
## [277] "withProgress" "withReactiveDomain"
## [279] "withTags"## no data sets foundwe will create a simple Shiny app that lets users choose a dataset and plot it..
#library(shiny)
# Define UI
ui <- fluidPage(
titlePanel("Simple Shiny App"),
sidebarLayout(
sidebarPanel(
selectInput("dataset", "Choose a dataset:",
choices = c("mtcars", "iris"))
),
mainPanel(
tableOutput("table")
)
)
)
# Define server logic
server <- function(input, output) {
output$table <- renderTable({
dataset <- get(input$dataset)
head(dataset) # Show the first few rows of the selected dataset
})
}
# Run the application
shinyApp(ui = ui, server = server)We can add custom features to make the app more interactive, such as adding sliders, filters, or reactive expressions. Let’s enhance the app by allowing users to filter data points based on a slider.s.
#install.packages("ggplot22")
library(ggplot2)
# Update UI with a slider for filtering
ui <- fluidPage(
titlePanel("Dataset Explorer with Filter"),
sidebarLayout(
sidebarPanel(
selectInput("dataset", "Choose a dataset:",
choices = c("mtcars", "iris")),
selectInput("xvar", "X-axis variable:", choices = NULL),
selectInput("yvar", "Y-axis variable:", choices = NULL),
sliderInput("obs", "Number of observations to display:",
min = 1, max = 100, value = 50)
),
mainPanel(
plotOutput("plot")
)
)
)
# Modify server logic for filtered data
server <- function(input, output, session) {
observeEvent(input$dataset, {
dataset <- get(input$dataset)
updateSelectInput(session, "xvar", choices = names(dataset))
updateSelectInput(session, "yvar", choices = names(dataset))
})
output$plot <- renderPlot({
dataset <- get(input$dataset)
dataset <- dataset[1:input$obs, ]
ggplot(dataset, aes_string(x = input$xvar, y = input$yvar)) +
geom_point() +
theme_minimal()
})
}
shinyApp(ui = ui, server = server)In this exercise, we: 1- Explored the shiny package and its documentation. 2- Built a basic Shiny app for exploring datasets. 3- Extended the app with a slider to control the number of observations displayed. This demonstrates how Shiny allows you to build interactive web applications quickly and extend them for more complex functionality.