CODEWITHSUNDEEP
rdataframeshiny
H.Ji
H.Ji

Reputation: 195

Is there any way to add rows to a data.frame recursively with a action button in shiny?

I want to realize a function that "When the user click an action button once, a row is added to a data frame". for example, add a row of [1,2,3] when clicking once. I tried the codes

res <- reactive({NULL})
res <- eventReactive({input$button, 
  rbind(res(), t(c(1,2,3)))
})

but, this cannot work. so, is there any way to achieve the aim ?

Upvotes: 2

Views: 380

Answers (2)

Florian
Florian

Reputation: 25385

I would personally use a reactiveVal and and observeEvent for this purpose as follows:

library(shiny)
ui <- fluidPage(
  actionButton('btn1','button'),
  dataTableOutput('table1')
)

server <- function(input,output){

  my_df <- reactiveVal(cars[1:5,])

  observeEvent(input$btn1,{
    # call old value with my_df(), rbind the new row, and set the new value 
    # by wrapping the statement with my_df()
    my_df(rbind(my_df(), c(1,2)))
  })

  output$table1 <- renderDataTable(
    my_df())
}

shinyApp(ui,server)

Upvotes: 5

amrrs
amrrs

Reputation: 6325

I am not sure why this is a tough ask. This is very straightforward with storing previous dataframe in a global variable and rbinding again and again.

Code:

library(shiny)
ui <- fluidPage(
  actionButton('btn1','button'),
  dataTableOutput('table1')
)

global_df <- cars[1:5,]

server <- function(input,output){

  new_df <- eventReactive(input$btn1,{

    global_df <<- rbind(global_df, c(1,2))
    global_df
  })

    output$table1 <- renderDataTable(
     new_df())



}


shinyApp(ui,server)

Upvotes: 0

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