Shiny R extract data from text file inputed by user - r

Question

I am working on a simple app that is supposed to ask for 1 (or more) unstructured text files, given by the user with fileInput. These files have all the same structure.
The idea is to make the cleaning/extraction on the background and give back the clean data to the user (ideally into a table).
I am fairly new using Shiny and the examples I have found basically indicate how to proceed when the file input is already in a clean and structured way.
Here is a simplified code that illustrates what I have done so far:
library(shiny)
shinyUI(fluidPage(
titlePanel(title = h2("Title", align = "left")),
sidebarLayout(position = "left",
sidebarPanel(h3("Data management window", align = "center"),
fileInput(inputId = "file_1",
label = "Select file 1")
),
mainPanel(
uiOutput(outputId = "tb")
)
)))
And here the server side:
shinyServer(function(input, output) {
input_file_1 <- reactive({
if(is.null(input$file_1)){
return("!! No data loaded !!")
}
readLines(input$file_1$datapath)
})
output$data_1 <- renderText({
fileText_1 <- paste(input_file_1(), collapse = "\n")
})
output$tb <- renderUI({
tabsetPanel(
tabPanel("Window 1",
br(),
tags$div(
tags$p("Summary infos : "),
tags$ul(
tags$li("Date calculation : ", Sys.Date()),
tags$li("Info 1: "),
tags$li("Info 2 : "),
tags$li("Info 3 : "),
br(),
verbatimTextOutput("data_1"))
))
)
})
})
At this stage I have managed to render the text of the file into the app. What I would like to do is to show in tabPanel some results obtained from the data extracted from the text file, like in the case of Sys.Date() but using values from the input file.
Do you have any ideas on how to proceed? Hope my question makes sense.

Answer 1

Your question is still too general, please more specific. But here is something to get you started. Using your server file and the iris dataset to make it easier, you can use the renderText() expression to extract the summary of one of your variable. And then you just add textOutput() expression in your tags$li("Info 1: ") argument.
Following a comment from OP, you could add a selectInput() that could help you pick one variable you want to summarise or extract information from. The code work as it is. Just replace iris by the file you will be loading.
ui = fluidPage(
titlePanel(title = h2("Title", align = "left")),
sidebarLayout(position = "left",
sidebarPanel(h3("Data management window", align = "center"),
fileInput(inputId = "file_1",
label = "Select file 1"),
uiOutput("Variable")
),
mainPanel(
uiOutput(outputId = "tb")
)
))
server = function(input, output) {
input_file_1 <- reactive({
if(is.null(input$file_1)){
return("!! No data loaded !!")
}
readLines(input$file_1$datapath)
})
output$data_1 <- renderText({
fileText_1 <- paste(input_file_1(), collapse = "\n")
})
output$Variable <- renderUI({
obj2 <- iris #replace by input_file_1()
selectInput("Variable", "Choose a variable", as.list(colnames(obj2)), multiple = FALSE)
})
output$summary1 <- renderPrint({
sub <- iris %>% select(input$Variable) #replace iris
a <- max(sub)
a
})
output$tb <- renderUI({
tabsetPanel(
tabPanel("Window 1",
br(),
tags$div(
tags$p("Summary infos : "),
tags$ul(
tags$li("Date calculation : ", Sys.Date()),
tags$li("Info 1: ", textOutput("summary1")),
tags$li("Info 2 : "),
tags$li("Info 3 : "),
br(),
verbatimTextOutput("data_1"))
))
)
})
}