Word cloud Shiny R

Question

I am wanting to make a word cloud using data from a postgresql table. I used an example as a base that I found on the Shiny R site, but I’m not able to do what I want.

I cannot change which variable will serve as the basis of the word cloud. Needed that when renaming the selection in "selectinput" the cloud should also change the variable that is used.

Server.R

function(input, output, session) {
# Define a reactive expression for the document term matrix
terms <- reactive({
# Change when the "update" button is pressed...
input$update
# ...but not for anything else
isolate({
  withProgress({
    setProgress(message = "Processing corpus...")
    getTermMatrix(input$selection)
  })
})
})

# Make the wordcloud drawing predictable during a session
wordcloud_rep <- repeatable(wordcloud)

output$plot <- renderPlot({
v <- terms()
wordcloud_rep(names(v), v, scale=c(4,0.5),
              min.freq = input$freq, max.words=input$max,
              colors=brewer.pal(8, "Dark2"))
})
}

Ui.R
fluidPage(
# Application title
titlePanel("Word Cloud"),

sidebarLayout(
# Sidebar with a slider and selection inputs
sidebarPanel(
  selectInput("selection", "Choose a book:",
              choices = c("Forzza","Viana")),
  actionButton("update", "Change"),
  hr(),
  sliderInput("freq",
              "Minimum Frequency:",
              min = 1,  max = 1000, value = 1),
  sliderInput("max",
              "Maximum Number of Words:",
              min = 1,  max = 100,  value = 100)
),

# Show Word Cloud
mainPanel(
 tabsetPanel(type = "tabs", 
     tabPanel("Plot", plotOutput("plot"))

)
)
)
)

Global.r
library(tm)
library(wordcloud)
library(memoise)

library(RPostgreSQL)
con <- dbConnect(PostgreSQL(), user="postgres",  password="123456",dbname="postgres")
coletor1=dbGetQuery(con,"SELECT REPLACE(aux_coletprinc,' ','')  aux_coletprinc  from jabot.detacesso2 where aux_coletprinc ilike '%forz%a%'
 limit 10")
coletor2=dbGetQuery(con,"SELECT REPLACE(aux_coletprinc,' ','')    aux_coletprinc  from jabot.detacesso2 where aux_coletprinc ilike '%vian%a%'
 limit 10")

dbDisconnect(con)

books <<- list("Forzza" ,
          "Viana" )


# Using "memoise" to automatically cache the results


getTermMatrix <- memoise(function(book) {
# Careful not to let just any name slip in here; a
# malicious user could manipulate this value.

text <- book    
myCorpus = Corpus(VectorSource(text))
myCorpus = tm_map(myCorpus, content_transformer(tolower))

myDTM = TermDocumentMatrix(myCorpus,
          control = list(minWordLength = 1))

m = as.matrix(myDTM)

sort(rowSums(m), decreasing = TRUE)

Answer 1

Your code has many problems. Below is a generic solution to the problem you described in the question: interactivity of the word cloud.

As you reported no problems with reading the data I isolated the functions of the RPostgreSQL and created "fantasy books". All you’ll need to do is swap the object books for something like books <<- list(coletor1, coletor2).

library(tm)
library(wordcloud)
library(memoise)
library(shiny)
library(stringr)

books <- list(Forzza = c("Um", "monte", "de", "palavras"),
              Viana = c("Outro", "texto", "vai", "aqui", "palavras"))

getTermMatrix <- memoise(function(text) {
  myCorpus = Corpus(VectorSource(text))
  myCorpus = tm_map(myCorpus, content_transformer(tolower))

  myDTM = TermDocumentMatrix(myCorpus,
                             control = list(minWordLength = 1))

  m = as.matrix(myDTM)

  sort(rowSums(m), decreasing = TRUE)
})

server <- shinyServer(function(input, output, session) {
    terms <- reactive({
      input$update
      isolate({
        withProgress({
          setProgress(message = "Processing corpus...")
          getTermMatrix(books[[input$selection]])
        })
      })
    })

    wordcloud_rep <- repeatable(wordcloud)

    output$plot <- renderPlot({
      v <- terms()
      wordcloud_rep(names(v), v, scale=c(4,0.5),
                    min.freq = input$freq, max.words=input$max,
                    colors=brewer.pal(8, "Dark2"))
    })
})

ui <- shinyUI(fluidPage(
  titlePanel("Word Cloud"),

  sidebarLayout(
    sidebarPanel(
      selectInput("selection", "Choose a book:",
                  choices = c("Forzza","Viana")),
      actionButton("update", "Change"),
      hr(),
      sliderInput("freq",
                  "Minimum Frequency:",
                  min = 1,  max = 1000, value = 1),
      sliderInput("max",
                  "Maximum Number of Words:",
                  min = 1,  max = 100,  value = 100)
    ),

    mainPanel(
      tabsetPanel(type = "tabs", 
                  tabPanel("Plot", plotOutput("plot"))

      )
    )
  )
))

shinyApp(ui = ui, server = server)