Shiny App - passing the string to variable - r

Question

I am trying to build Shiny App that does sentiment analysis. I have the code that works fine when i execute the script normally where Rstudio is importing the data from email.csv file. This file contains only 2 columns ( SentTo and RawText) and the text i am analyzing is located in B2 cell.
Once i run the code below i get nice chart that measure the sentiment.
library(readr)
library("ggplot2")
library('syuzhet')
Emails <- read_csv("C:/email.csv")
d<-get_nrc_sentiment(Emails$RawText)
td<-data.frame(t(d))
td_new <- data.frame(rowSums(td[1:14]))
names(td_new)[1] <- "count"
td_new <- cbind("sentiment" = rownames(td_new), td_new)
rownames(td_new) <- NULL
td_new2<-td_new[1:8,]
qplot(sentiment, data=td_new2, weight=count,
geom="bar",fill=sentiment)+ggtitle("Email sentiments")
Now what i am trying to do is to modify this code a bit and build the Shiny application by doing next:
ui.R
# Adding the Imput text field to the app
shinyUI(fluidPage(
textAreaInput("UserInput", "Caption", "Please Enter Your Text", width =
"500px", height = "300px"),
mainPanel(
plotOutput("distPlot"))
))
Server.R
library(shiny)
library(syuzhet)
library(ggplot2)
# Define server logic required to draw a histogram
shinyServer(function(input, output) {
output$distPlot <- renderPlot({
Emails <- input$UserInput
d<-get_nrc_sentiment(Emails)
td<-data.frame(t(d))
td_new <- data.frame(rowSums(td[1:14]))
names(td_new)[1] <- "count"
td_new <- cbind("sentiment" = rownames(td_new), td_new)
rownames(td_new) <- NULL
td_new2<-td_new[1:8,]
qplot(sentiment, data=td_new2, weight=count,
geom="bar",fill=sentiment)+ggtitle("Email sentiments")
})
})
After i run the app i get this error:
So ti builds the app but even when i paste some text in to the field it seems that the code i am using in server.R part is not doing what it needs to do.
If i replace the line in server.R part (Emails <- input$UserInput) with (Emails <- read_csv("C:/email.csv"))
than it works fine. This tells me that the issue is within the way i am passing the text to the Emails. Through the input form its text through the csv file it is a second row and second column that contains the data. The code that follows i think its looking that specific format.
Anybody has suggestion on how to modify this to make it work?
Thank you in advance.

Answer 1

I believe the issue is in line:
td_new <- data.frame(rowSums(td[1:14]))
If I change it to the following, it works for me:
td_new <- data.frame(rowSums(td))
I'm not sure why you had the 1:14 index in there, but I don't see what it does.

Answer 2

Before plotting in shiny, first have it output the user input so that you understand what is being passed to the next step. verbatimTextOutput('input$UserInput') and verbatimTextOutput('dput(input$UserInput)'). I'm guessing this will be a character vector of length 1.
Now, go back to your code outside of shiny and pass it this same input, formatted exactly the same. Right now your code that works is getting a data.frame from a csv file and passed a column, which would be a character vector.
Once you get it working outside of shiny, using the input as parsed by shiny, the fixes to make your shiny app work should be clear.