26/09/2024

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Course modules

  • Overview, understanding problem and getting data
  • Exploratory dat analysis and modelling
  • Prediction model
  • Creative exploration
  • Data product
  • Slide deck

Structure of a Shiny App

  • Shiny apps are contained in a single script called app.R. The script app.R lives in a directory (for example, newdir/) and the app can be run with runApp(“newdir”).

  • app.R has three components:

    • a user interface object,
    • a server function,
    • a call to the shinyApp function.

  • The user interface (ui) object controls the layout and appearance of your app. The server function contains the instructions that your computer needs to build your app. Finally the shinyApp function creates Shiny app objects from an explicit UI/server pair.

Creating ui.R file

  • Install necessary packages and library.
  • Sample code shinyUI(fluidPage( # Application title titlePanel(“Predict Next Word”), h6(“it may take several seconds”), # Sidebar with a slider input for number of n gram sidebarLayout( sidebarPanel( sliderInput( inputId = “Ngram”, label = “Select N for Ngram:”, min = 1,max = 20,value = 3, step = 1), textInput(“inputString”, “Enter a partial sentence here”,value = ’‘), submitButton(“Submit”, icon(“refresh”))), mainPanel( h2(“Predicted Next Word”), strong(“Sentence Input:”), tagsstyle(type=′text/css′),textOutput(′text1′),strong(“SentenceswithNextWordCandidates:”),textOutput(“prediction”),strong(“Note:”),tags style(type=’text/css’), textOutput(‘text2’)))))

Creating server.R file

  • corpus <- readRDS(‘corpus.RData’)
  • BackoffModels <- function(n){ BackoffModel <<- list() for(i in 2:n){ BackoffModel[[paste(i,“grams”)]] <<- createNgrams(corpus,i)}}
  • createNgrams <- function(text, n){ ngram <- function(x) NGramTokenizer(x, Weka_control(min = n, max = n)) ngrams <- TermDocumentMatrix(text, control = list(tokenize = ngram)) ngrams_freq <- rowSums(as.matrix(ngrams)) ngrams_freq <- sort(ngrams_freq, decreasing = TRUE) ngrams_freq_df <- data.frame(word = names(ngrams_freq), freq=ngrams_freq) ngrams_freq_df}

Thank you