How to edit an uploaded data in rshiny - r

Question

Here are the requirements.
1)I need to browse and upload an excel file (with package readxl), which is used to arrive at some calculations which I need to display in shiny window as a different table output
2) Manually edit some data in the uploaded file and it should automatically reflect in the results displayed
3) We should be able to download the edited file.
I have written so far. I have columns ID, exposure and frequency in input data. For each ID I need to calculate a variable using corresponding exposure and frequency which would be displayed. I need to manually edit frequency and Exposure using ID ( which is unique ). I have added an "update" button. But change is not permanent. It goes back as soon as I click update button once more
library(shiny)
ui = fluidPage(
titlePanel("HEllo world"),
sidebarLayout(
sidebarPanel(
fileInput('file1', 'Choose xlsx file',
accept = c(".xlsx")),
actionButton("go", "update"),
numericInput('NewVal', 'Enter new Frequency',NULL),
numericInput('NewExp', 'Enter new Exposure',NULL)),
mainPanel(
textInput('ID', 'Enter ID'),
dataTableOutput('contents')
)))
server = function(input,output){
ef <- eventReactive(input$go, {
infile <- input$file1
if(is.null(infile))
return(NULL)
file.rename(infile$datapath,paste(infile$datapath, ".xlsx", sep=""))
data<-read_excel(paste(infile$datapath, ".xlsx", sep=""), 1)
if(input$ID!="" && input$go>0){
for( i in 1:nrow(data)){
if( input$ID == data$'ID'[i]){
if(!is.na(input$NewVal)){
data$' Frequency'[i] <- input$NewVal
}
if(!is.na(input$NewExp)){
data$'Exposure'[i] <- input$NewExp
}
}}}
data
}, ignoreNULL = FALSE)
output$contents <- renderDataTable({ef()})}
shinyApp(ui,server)
UPDATE!:As per one answer, I have made some changes to my code. The new code seems to be working fine. Here is the working code, for anyone who might need help with the same issue.
ui = fluidPage(
titlePanel("HEllo world"),
sidebarLayout(
sidebarPanel(
fileInput('file1', 'Choose xlsx file',
accept = c(".xlsx")),
actionButton("go", "update"),
numericInput('NewVal', 'Enter new Frequency',NULL),
numericInput('NewExp', 'Enter new Exposure',NULL)),
mainPanel(
textInput('ID', 'Enter ID'),
tableOutput('contents')
)))
server = function(input,output){
# Reactive value to save input data frame for use elsewhere
original <- reactiveValues()
observeEvent(input$file1, {
theFile <- input$file1
if(is.null(theFile)) {
return(NULL)}
**file.rename(theFile$datapath,paste(theFile$datapath, ".xlsx", sep=""))**
original$oldData <- read_excel(paste(theFile$datapath, ".xlsx", sep = ""), 1)
})
observeEvent(input$go, {
original$newData <- original$oldData
if(input$ID !="") {
for( i in 1:nrow(original$oldData)){
if( input$ID == original$oldData$'ID'[i]){
if(!is.na(input$NewVal)){
original$newData$'Frequency'[i] <- input$NewVal
}
if(!is.na(input$NewExp)){
original$newData$'Exposure'[i] <- input$NewExp
}
}
}
**original$oldData<-original$newData** }
})
output$contents <- renderTable({
if(!is.null(original$newData)) {
original$newData}
else {
original$oldData}
})
}
shinyApp(ui = ui, server = server)

Answer 1

Some of the comments seem to be on the right track of what's going on here. There's several solutions that could be used, but I'll just share what's most intuitive to me. Also, I'll only be changing the server function.
server = function(input,output){
# Reactive value to save input data frame for use elsewhere
original <- reactiveValues()
observeEvent(input$file1, {
theFile <- input$file1
if(is.null(theFile)) {return(NULL)}
original$oldData <- read_excel(paste(theFile$datapath, ".xlsx", sep = ""), 1)
})
observeEvent(input$goButton2, {
original$newData <- original$oldData
if(input$ID !="") {
for( i in 1:nrow(data)){
if( input$ID == dat$'ID'[i]){
if(!is.na(input$NewVal)){
original$newData$' Frequency'[i] <- input$NewVal
}
if(!is.na(input$NewExp)){
original$newData$'Exposure'[i] <- input$NewExp
}
}
}
}
})
output$contents <- renderDataTable({
if(!is.null(original$newData)) {original$newData}
else {original$oldData}
})
}
This won't change the table output until the go button is clicked. I haven't tested it fully, since I don't have your data, but I believe this should set you on the right track at the bare minimum... I like observe statements, because they cause side effects and seem more open ended than eventReactives or functions.
This only helps with the initial issues of having the correct changes made and continued showing in the output. If this works, it should be fairly easy to add a download function, which saves the file whenever it's updated.
Update 1
The code below should do what you would want it to do. I've added two different capabilities for saving the new data frame. The commented out code saves the data automatically whenever the update button is pressed. The code that's there without comments around it creates a download button for downloading the data. I've also added a line that calculates a new value based off frequency and exposure. Named this column Value in data set. Hope this helps!
#### Example app for Exchange answer
library(shiny)
library(readxl)
ui = fluidPage(
titlePanel("HEllo world"),
sidebarLayout(
sidebarPanel(
fileInput('file1', 'Choose xlsx file',
accept = c(".xlsx")),
actionButton("go", "update"),
numericInput('NewVal', 'Enter new Frequency',NULL),
numericInput('NewExp', 'Enter new Exposure',NULL),
# Download button (goes with download handler below)
# Use if desire is to save at press of button
downloadButton("save", "Download")
),
mainPanel(
textInput('ID', 'Enter ID'),
dataTableOutput('contents')
)
)
)
server = function(input,output){
# Reactive value to save input data frame for use elsewhere
original <- reactiveValues()
observeEvent(input$file1, {
theFile <- input$file1
if(is.null(theFile)) {
original$oldData <- NULL
} else {
original$oldData <- read_excel(theFile$datapath, 1)
}
})
observeEvent(input$go, {
original$newData <- original$oldData
if(input$ID !="") {
for(i in 1:nrow(original$oldData)){
if(input$ID == original$oldData$'ID'[i]){
if(!is.na(input$NewVal)){
original$newData$'Frequency'[i] <- input$NewVal
}
if(!is.na(input$NewExp)){
original$newData$'Exposure'[i] <- input$NewExp
}
### Make sure a column in your data set is named Value for this
# Calculate a new column
original$newData$'Value'[i] <- (original$newData$'Exposure'[i]*
original$newData$'Frequency'[i])
}
}
original$oldData<-original$newData
}
### Use this to automatically save table when update is clicked
# write.csv(original$newData,
# file = #Desired Pathname,
# row.names = FALSE)
})
output$contents <- renderDataTable({
if(!is.null(original$newData)) {
original$newData}
else {
original$oldData
}
})
### Use this code below if desired saving is through download button
# Server code for download button
output$save <- downloadHandler(
filename = function() {
paste0("newData - ", Sys.Date(), ".csv")
},
content = function(con) {
if (!is.null(original$newData)) {
dataSave <- original$newData
} else {
dataSave <- original$oldData
}
con <- ## Desired save location... could just use `getwd()` to
# save to working directory
write.csv(dataSave, con)
}
)
}
shinyApp(ui = ui, server = server)