R help - Dec 2012 - Reading JSON files from R

Hello All -

I am trying to use RJSONIO to read in some JSON files.

I was wondering if anyone could please comment on the level of complexity of
the files it can be used to read, exports from or directly from NoSQL DBMS
like MongoDB and such.

Also, i understand that in reading the JSON file RJSONIO will automatically
create the necessary structures. However I cannot seem to use to to read the
file properly and get this error:

Error in function (classes, fdef, mtable)  : 
  unable to find an inherited method for function "fromJSON", for
signature
"missing", "NULL"

The call I am making is:
noSqlData <- fromJSON(file='data.json')

It is a small file - with 3 levels of nested records.

And if there were some links to some examples with a file and usage would be
great. My JSON file validates - so do not believe there is anything wrong
with the file.

Thanks for your help.





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Hi m.dr.

  Reading data from MongoDB is no problem. So the RJSONIO or rjson
packages should work.

  Can you send me the sample file that is causing the problem, please?

 The error about a method looks like a potential oversight in the combinations
of inputs.

  Thanks
    D.




On 12/3/12 7:30 PM, m.dr wrote:
> Hello All -
> 
> I am trying to use RJSONIO to read in some JSON files.
> 
> I was wondering if anyone could please comment on the level of complexity
of
> the files it can be used to read, exports from or directly from NoSQL DBMS
> like MongoDB and such.
> 
> Also, i understand that in reading the JSON file RJSONIO will automatically
> create the necessary structures. However I cannot seem to use to to read
the
> file properly and get this error:
> 
> Error in function (classes, fdef, mtable)  : 
>   unable to find an inherited method for function "fromJSON", for
signature
> "missing", "NULL"
> 
> The call I am making is:
> noSqlData <- fromJSON(file='data.json')
> 
> It is a small file - with 3 levels of nested records.
> 
> And if there were some links to some examples with a file and usage would
be
> great. My JSON file validates - so do not believe there is anything wrong
> with the file.
> 
> Thanks for your help.
> 
> 
> 
> 
> 
> --
> View this message in context:
http://r.789695.n4.nabble.com/Reading-JSON-files-from-R-tp4651976.html
> Sent from the R help mailing list archive at Nabble.com.
> 
> ______________________________________________
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> PLEASE do read the posting guide
http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
> 
>