-Re: How to filter by pig datatype?
pablomar 2012-11-22, 17:48
did you try with a filter function ?
public class IsMap extends FilterFunc
public Boolean exec(Tuple input) throws IOException
if (input == null || input.size() == 0)
return(input.get(0) instanceof java.util.Map);
throw WrappedIOException.wrap("ouch!", e);
filtered = FILTER some_data BY IsMap(some_variable);
PS: I didn't try it with your data
On Wed, Nov 21, 2012 at 8:54 PM, Lex H <[EMAIL PROTECTED]> wrote:
> Attached is a tiny testcase illustrating my problem.
> What I would like to know is how to filter by Pig datatype.
> e.g. something like:
> filtered = FILTER some_data BY some_variable IS_MAP_TYPE;
> Can anyone advise if this can be accomplished with Pig?
> We have a field that is sometimes a 'map' sometimes a chararray.
> Doing something like the following statement fails, presumable because
> it's trying to a key-value lookup on something that's not a 'map'.
> -- json#'data' is sometimes a map, sometimes not.
> trivias = FOREACH data GENERATE json#'data'#'trivia' AS trivia:charray;
> This has come about from us working with JSON data with Pig via Elephant
> Bird's JsonLoader.