Writing a data.frame into a spreadsheet: Encoding problems

Question

I have extraced some data from Instagram. All of the API request are done by

fromJSON(rawToChar(GET(url)$content))

When I try to display that dataframe within a Shiny application using renderTable() I get the error message

Error in sort.list(y) : 
  invalid input 'Ivy Manhattan í ¼í½‰' in 'utf8towcs'

Ok, it looks like an encoding problem. Ivy Manhattan í ¼í½‰ is the full name of a Instagram user. Intersting is, that the output is being rendered properly when I use rederDataTable(). Sure, why dont I just use it then?

The actual problem is, that I want to be able to write this dataframe to a spreadsheet using the package XLConnect. And when the program reaches the command writeWorksheet(wb, data) I get the same error.

Is it because those characters are unknown to R? How can I "filter" the dataframe for problematic strings?

First Edit as reaction to MrFlick's comment:

Well what I get when I fetch a request to the API is

GET(paste("https://api.instagram.com/v1/users/143/?client_id=f714dd*********58b18f"))$content

[1] 7b 22 6d 65 74 61 22 3a 7b 22 63 6f 64 65 22 3a 32 30 30 7d 2c 22 64 61 74 61 22  3a 7b 22 75 73 65 72 6e 61 6d 65 22 ... AND SO ON

rawToChar() converts that to the JSON string which is readable/accepted by fromJSON()

@MrFlick Second edit:

Here is the output of Sys.getlocale() from my machine:

> Sys.getlocale()
[1] "LC_COLLATE=German_Germany.1252;LC_CTYPE=German_Germany.1252
LC_MONETARY=German_Germany.1252;LC_NUMERIC=C;LC_TIME=German_Germany.1252"

GET declares the fetched string as encoded with utf-8. When I try to convert those with

iconv(x, from="utf-8", to="ASCII",sub="")

Nothing changes.

Answer 1

I tried to just encode the JSON part data$fullname since that seems to be the problem. I tried Encoding(data$fullname) = "UTF-8" at first which didnt resolve the situation. But then I switched to latin1and the spreadsheet happend to be written. Thanks for your pushy ideas! :)