How to use test.R to unmerge the column using R shiny - r

Question

After I get the column name from the user, I want to unmerge the column 'alpha.'
I have the dataframe, and I have the same dataframe on my system as a csv file. (I'm highlighted the dataframe here for clarity) -> All of the following is occurring in the r script named test.R
What I'm looking for is a way to use test.R When I click the "Unmerge" button in R shiny, I should get the results (with unmerging columns) and the final dataset should render in the main panel.
Since I'm new to R Shiny, I'm not sure how to go about doing it.
Could someone please help me?
Note: The browse button should take the same data frame as csv and provide the unmerged results in the main panel.
test.R
library(dplyr)
library(tidyr)
library(stringr)
library(tidyverse)
library(stringr)
library(svDialogs)
column_name <- dlg_input("Enter a number", Sys.info()["user"])$res
before_merge<- data.frame(ID=21:23, alpha=c('a b', 'c d', 'e z'))
before_merge
library(reshape2)
newColNames <- c("type1", "type2")
#column_name <- readline(prompt="Enter the desired column name: ")
newCols <- colsplit(before[[column_name]], " ", newColNames)
after_merge <- cbind(before, newCols)
after[[column_name]] <- NULL
after_merge
Shiny App
## Only run examples in interactive R sessions
library(shiny)
if (interactive()) {
ui <- fluidPage(
sidebarLayout(
sidebarPanel(
fileInput("file1", "Choose CSV File", accept = ".csv"),
checkboxInput("header", "Header", TRUE),
actionButton("dataset2", "Extract", class = "btn-primary"),
),
mainPanel(
tableOutput("contents")
)
)
)
server <- function(input, output) {
output$contents <- renderTable({
file <- input$file1
ext <- tools::file_ext(file$datapath)
req(file)
validate(need(ext == "csv", "Please upload a csv file"))
read.csv(file$datapath, header = input$header)
})
observeEvent(input$dataset2, {
source("test.R", local = TRUE)
})
}
shinyApp(ui, server)
}

Answer 1

So what you want to do is twofold:
First, remove the dialog input from test.R and put in a corresponding input in Shiny itself. This is to identify the column, right? You can make a selectInput with the options being the column names that the dataframe has.
Next, put all the relevant code into a function. This function should do the following: take in an input dataframe (you are creating this before_merge in test.R, instead, use the dataframe that you are getting from the upload), do whatever you need to do (the colsplit, etc.), and then return the final result.
Once you have that, then it's just a matter of putting a line at the top of your Shiny file where you source your test.R, and then you can call the function directly.
Alternatively, you don't even need a separate test.R file - just put your function above the output$contents section and use it directly. It's useful to have a separate helper file if you have a lot of functions (or the functions are used elsewhere), but in this case you don't need it.