Color highlighting text in R for a pre-defined list of words

Question

Suppose I have a collection of documents such as:

text = c("is it possible to highlight text for some words" , 
      "suppose i want words like words to be red and words like text to be blue")

I am wondering whether it is possible to highlight documents (particularly for a large corpus) with colors for a pre-defined list of words using R. Each word in the list will get a specific color. For example, highlighting "words" to be red and "text" to be blue as shown below.

Answer 1

Here is the full debugged app code!

First, required libraries:

library(shiny)
library(tidyverse)
library(DT)
library(magrittr)

Then, the function that adds HTML tag:

wordHighlight <- function(SuspWord,colH = 'yellow') {
  paste0('<span style="background-color:',colH,'">',SuspWord,'</span>')
}

Now UI portion:

ui <- fluidPage(
   titlePanel("Text Highlighting"),
   sidebarLayout(
      sidebarPanel(
        textInput("wordSearch", "Word Search")
      ),
    mainPanel(
        DT::dataTableOutput("table")
      )   
   )  
   )

Finally, on the server side:

server <- function(input, output) {
   sentence <- "The term 'data science' (originally used interchangeably with 'datalogy') has existed for over thirty years and was used initially as a substitute for computer science by Peter Naur in 1960."
   sentence2 = "One of the things we will want to do most often for social science analyses of text data is generate a document-term matrix."
   YourData = data.frame(N = c('001','002'), T = c(sentence,sentence2), stringsAsFactors=FALSE)
   highlightData <- reactive({
     if (input$wordSearch!="")
      {
        patterns = input$wordSearch
        YourData2 = YourData
        YourData2[,2] %<>% str_replace_all(regex(patterns, ignore_case = TRUE), wordHighlight)
        return(YourData2)
      }
    return(YourData)
  })
    output$table <- DT::renderDataTable({
      data <- highlightData() 
    }, escape = FALSE)
}

Run the app:

shinyApp(ui = ui, server = server)