Daniel Dai created PIG-2739:
-------------------------------
Summary: PyList should map to Bag automatically in Jython
Key: PIG-2739
URL: https://issues.apache.org/jira/browse/PIG-2739
Project: Pig
Issue Type: Bug
Components: impl
Affects Versions: 0.10.0, 0.11
Reporter: Daniel Dai
Assignee: Daniel Dai
The following script does not work:
<code>
register 'util.py' using jython as util;
A = load '1.txt' as (sentence:chararray);
B = foreach A generate flatten(util.tokenize(sentence));
dump B;
<code>
util.py
<code>
outputSchema("words:{(word:chararray)}")
def tokenize(sentence):
return sentence.split(' ')
<code>
Error message:
org.apache.pig.backend.executionengine.ExecException: ERROR 2078: Caught error
from UDF: org.apache.pig.scripting.jython.JythonFunction [Error executing
function]
at
org.apache.pig.backend.hadoop.executionengine.physicalLayer.expressionOperators.POUserFunc.getNext(POUserFunc.java:288)
at
org.apache.pig.backend.hadoop.executionengine.physicalLayer.expressionOperators.POUserFunc.getNext(POUserFunc.java:304)
at
org.apache.pig.backend.hadoop.executionengine.physicalLayer.PhysicalOperator.getNext(PhysicalOperator.java:332)
at
org.apache.pig.backend.hadoop.executionengine.physicalLayer.relationalOperators.POForEach.processPlan(POForEach.java:353)
at
org.apache.pig.backend.hadoop.executionengine.physicalLayer.relationalOperators.POForEach.getNext(POForEach.java:294)
at
org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.PigGenericMapBase.runPipeline(PigGenericMapBase.java:273)
at
org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.PigGenericMapBase.map(PigGenericMapBase.java:268)
at
org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.PigGenericMapBase.map(PigGenericMapBase.java:64)
at org.apache.hadoop.mapreduce.Mapper.run(Mapper.java:144)
at org.apache.hadoop.mapred.MapTask.runNewMapper(MapTask.java:764)
at org.apache.hadoop.mapred.MapTask.run(MapTask.java:370)
at
org.apache.hadoop.mapred.LocalJobRunner$Job.run(LocalJobRunner.java:212)
Caused by: java.io.IOException: Error executing function
at
org.apache.pig.scripting.jython.JythonFunction.exec(JythonFunction.java:122)
at
org.apache.pig.backend.hadoop.executionengine.physicalLayer.expressionOperators.POUserFunc.getNext(POUserFunc.java:262)
... 11 more
Caused by: org.apache.pig.backend.executionengine.ExecException: ERROR 0:
Cannot convert jython type (org.python.core.PyList) to pig datatype
java.lang.ClassCastException: java.lang.String cannot be cast to
org.apache.pig.data.Tuple
at
org.apache.pig.scripting.jython.JythonUtils.pythonToPig(JythonUtils.java:113)
at
org.apache.pig.scripting.jython.JythonFunction.exec(JythonFunction.java:117)
... 12 more
Caused by: java.lang.ClassCastException: java.lang.String cannot be cast to
org.apache.pig.data.Tuple
at
org.apache.pig.scripting.jython.JythonUtils.pythonToPig(JythonUtils.java:69)
... 13 more
The problem is Pig expects a tuple inside a list, which is unintuitive in
Python.
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