How to download editable data table in shiny - r

Question

In data table, we can use argument editable to make the table editable. I'm making a shiny app in which table is both editable and downloadable.
My question is how I can download a datatable after I edit it?
Here is my app code:
library(shiny)
library(DT)
server <- function(input, output) {
df = iris
output$data = DT::renderDataTable ({
DT::datatable(df, editable = list(
target = 'row',
disable = list(columns = c(1, 3, 4))
))
})
output$downloadData <- downloadHandler(
filename = function() {
#paste(input$dataset, ".csv", sep = "")
},
content = function(file) {
write.csv(df, file, row.names = FALSE)
}
)
}
ui <- fluidPage(
DT::dataTableOutput('data'),
downloadButton("downloadData", "Download")
)
shinyApp(ui = ui, server = server)

Answer 1

When you edit a cell of a datatable named "XXX", the info about the cell edit is in input$XXX_cell_edit. This info contains the indices of the edited cell and its new value. So you can do:
library(shiny)
library(DT)
dat <- iris[1:3, ]
ui <- fluidPage(
downloadButton("downloadData", "Download"),
DTOutput("table")
)
server <- function(input, output){
output[["table"]] <- renderDT({
datatable(dat, editable = "cell")
})
df <- reactiveVal(dat)
observeEvent(input[["table_cell_edit"]], {
cell <- input[["table_cell_edit"]]
newdf <- df()
newdf[cell$row, cell$col] <- cell$value
df(newdf)
})
output[["downloadData"]] <- downloadHandler(
filename = function() {
"mydata.csv"
},
content = function(file) {
write.csv(df(), file, row.names = FALSE)
}
)
}
shinyApp(ui, server)
Alternatively, as suggested by #MrGumble, you can use the embedded button of Datatables instead of a downloadHandler. This is more stylish.
library(shiny)
library(DT)
dat <- iris[1:3, ]
ui <- fluidPage(
DTOutput("table")
)
server <- function(input, output){
output[["table"]] <- renderDT({
datatable(dat, editable = "cell", extensions = "Buttons",
options = list(
dom = "Bfrtip",
buttons = list(
"csv"
)
))
})
observeEvent(input[["table_cell_edit"]], {
cellinfo <- input[["table_cell_edit"]]
dat <<- editData(dat, input[["table_cell_edit"]], "table")
})
}
shinyApp(ui, server)

Answer 2

You can add a download button directly to a DT datatable, which offers the user to download the current data in the table, see R Shiny: How to add download buttons in DT::renderDataTable
If you however want to use the edited data for server-side calculations, you are are on the right track, but need to save the edited table into the data.frame using replaceData. See e.g. https://yihui.shinyapps.io/DT-edit/