performing operations after uploading a CSV file in shiny [R] -

i have made upload button via uploading .csv file[dataset] in shiny.

dataframe <- data.frame(a=c(2,3,4,5,6,7,3,7,8,9,2),b=c(3,7,8,9,2,1,2,3,4,5,6),c=c(1,1,1,2,2,1,1,1,1,2,2)) 

in ui.r :

fileinput('datafile', 'choose csv file',      accept=c('csv', 'comma-separated-values','.csv')),      actionbutton("uploaddata", "upload"), 

i want perform operations such "a+b" , "a-b" on dataset , add new column in dataset of actionbutton.

problem 1: tried use tableoutput() function display data in shinyapp displaying data dataframe in r console instead.

in server.r:

data <- dataframe %>% group_by(c) %>% mutate(a) %>%  mutate(b) %>% mutate(add = (a+b)) %>% mutate(sub = (a-b)) 

problem 2: want use data input making ggplots of (add, sub)

you this:

ui.r

library(shiny)  shinyui(fluidpage(         fileinput('datafile', 'choose csv file',                 accept=c('csv', 'comma-separated-values','.csv')),         tableoutput('table'),         plotoutput('plot')         )) 

server.r

library(shiny) library(ggplot2)  shinyserver(function(input, output,session) {          dataframe<-reactive({                 if (is.null(input$datafile))                         return(null)                                 data<-read.csv(input$datafile$datapath)                 data<- data %>% group_by(c) %>% mutate(a) %>%                          mutate(b) %>% mutate(add = (a+b)) %>% mutate(sub = (a-b))                 data         })         output$table <- rendertable({                 dataframe()         })         output$plot <- renderplot({                 if(!is.null(dataframe()))                         ggplot(dataframe(),aes(x=x,y=add))+geom_point()         }) }) 

i removed action button because fileinput load file directly once user has chosen it. in server.r, loaded dataframe stored in reactive value, can call dataframe() when want make plot/render table dataframe.

you might want code check csv file has , b column etc.