Compare CSV files from two dropdowns Rshiny - r

Question

How can I create a shiny app with two dropdown menus with csv files from ./data folder then read those Csv and compare differences?
A user selects CSV from two dropdown menus then automatically generates differences
UI.R
library("shiny")
ui <- fluidPage(
fluidPage(
titlePanel("Automated Data Dictionary Comparison"),
sidebarLayout(
sidebarPanel(
selectInput(inputId = 'Dic1',
label = 'Choose First Data Dictionary:',
choices = list.files(path = "./data",
full.names = FALSE,
recursive = FALSE)),
selectInput(inputId = 'Dic2',
label = 'Choose Second Data Dictionary:',
choices = list.files(path = "./data",
full.names = FALSE,
recursive = FALSE))
),
mainPanel(
tableOutput('contents')
)
)
)
)
SERVER.R
Library(shiny)
library(dplyr)
server <- function(input, output) {
dataset <- reactive({
infile <- input$Dic1
if (is.null(infile)){
return(NULL)
}
read.csv(infile[[1]])
})
output$contents <- renderDataTable({
#x <- dataset()
Diff <- render_diff(diff_data(data_ref=input$DIC1, data = input$DIC2),
Diff
})
}

Answer 1

From what I can see here, what you are doing is that you are correctly creating your reactive dataset object dataset (for 1 of your input files though not both), but you are not using this later on, when you want to generate the differences table (which again needs to be a reactive component as it will be generated from 2 reactive ones - dataset1 and dataset2).
Something like this should do the trick though (wrap it inside the server function):
# Parse first file
dataset1 <- reactive({
infile <- input$Dic1
if (is.null(infile)){
return(NULL)
}
x <- read.csv(infile[[1]])
x
})
# Parse second file
dataset2 <- reactive({
infile <- input$Dic2
if (is.null(infile)){
return(NULL)
}
x <- read.csv(infile[[1]])
x
})
# Create comparison table (reactive as both of its elements are reactive)
diff <- reactive({
x <- render_diff(diff_data(data_ref=dataset1(), data=dataset2()))
x
})
#Output
output$contents <- renderDataTable({
diff()
})
Check the above and let me know how it goes for you.