read a file and save it into an object. [No display of loaded data ] in Shiny R

Question

I know there are a few questions asked about this here is SO.

But I couldn't figure out the solution to my problem from them.

I want to Upload a file into R through shiny and assign it to an object say the object name "Object_name".

I used fileInput in ui.R and did this

fileInput('file1', h4('Choose Your Data File'),
                            accept=c('text/csv',
                                     'text/comma-separated-values,text/plain',
                                     '.OUT'))

Now I accesses the "file1" and tried to recover my uploaded file through file1$datapath. I couldn't actually do this. I am getting console errors like....

1. Error in terms.formula(formula, data = data) : 
  'data' argument is of the wrong type

And in GUI in the plot plane its showing Error:'data' argument is of the wrong type

I have added this piece of code in shinyserver server.R

mydata <- reactive({
    inFile <- input$file1
    if (is.null(inFile)) return(NULL)
    object_name <- read.table(inFile$datapath, header = TRUE)
  })

Is it allowed to access the file directly from the datapath as I am doing above. Why doesn't it load the uploaded data into "a".

If somebody knows the answer please help me out.

Update:

My dataset is of header = False. So once I upload the data I have to change the names(my dataset) and then further calculations can be performed.

Considering this code

a <- reactive({
   inFile <- input$file1
   if (is.null(inFile)) return(NULL)
   read.table(inFile$datapath, header = TRUE)
 })

Still I cant access the a() [i,e the data I want] and use it into further calculations. I cant assign like names(a) <- c(.......) outside reactive because it throws error if I do that ...

Error in names(a) <- c("Ei", "Mi", "hours", "Nphy", "Cphy", "CHLphy",  : 
  names() applied to a non-vector

And I cant do it inside reactive because I can only assign names once the data "a" or "a()" is ready. so how can I achieve this.

John Paul John Paul · Accepted Answer · 2014-08-22T19:08:51

In your server.r you need to do read.csv (or whatever corresponds to your input file format) to get at the data. Something like:

MyData<-reactive({ read.csv(input$file1$datapath, ...) })

Where ... is whatever other arguments that you need for read.csv(). Then you can access your data by referring to it as MyData().

Edit If you want to add column names (that aren't in the original .csv) they you can use the col.names argument in read.csv().

read a file and save it into an object. [No display of loaded data ] in Shiny R

1 Answers