datafu.pig.util
Class TransposeTupleToBag

java.lang.Object
  org.apache.pig.EvalFunc<T>
      datafu.pig.util.ContextualEvalFunc<T>
          datafu.pig.util.AliasableEvalFunc<org.apache.pig.data.DataBag>
              datafu.pig.util.TransposeTupleToBag

public class TransposeTupleToBag
extends AliasableEvalFunc<org.apache.pig.data.DataBag>

Performs a transpose on a tuple, resulting in a bag of key, value fields where the key is the column name and the value is the value of that column in the tuple.

Example:

 define TransposeTupleToBag datafu.pig.util.TransposeTupleToBag();

 -- input: 1,10,11,12
 input = LOAD 'input' AS (id:int,val1:int,val2:int,val3:int);

 -- produces: 1,{("val1",10),("val2",11),("val3",12)}
 output = FOREACH input GENERATE id, TransposeTupleToBag(val1 .. val3);

 
 

Author:

"William Vaughan "

Field Summary

Fields inherited from class org.apache.pig.EvalFunc

log, pigLogger, reporter, returnType

Constructor Summary

TransposeTupleToBag()

Method Summary

org.apache.pig.data.DataBag	exec(org.apache.pig.data.Tuple input)
org.apache.pig.impl.logicalLayer.schema.Schema	getOutputSchema(org.apache.pig.impl.logicalLayer.schema.Schema input) Specify the output schema as in {link EvalFunc#outputSchema(Schema)}.

Methods inherited from class datafu.pig.util.AliasableEvalFunc

getBag, getBoolean, getDouble, getDouble, getFieldAliases, getFloat, getFloat, getInteger, getInteger, getLong, getLong, getObject, getPosition, getPosition, getPrefixedAliasName, getString, getString, outputSchema

Methods inherited from class datafu.pig.util.ContextualEvalFunc

getContextProperties, getInstanceName, getInstanceProperties, setUDFContextSignature

Methods inherited from class org.apache.pig.EvalFunc

finish, getArgToFuncMapping, getCacheFiles, getInputSchema, getLogger, getPigLogger, getReporter, getReturnType, getSchemaName, isAsynchronous, progress, setInputSchema, setPigLogger, setReporter, warn

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

TransposeTupleToBag

public TransposeTupleToBag()

Method Detail

getOutputSchema

public org.apache.pig.impl.logicalLayer.schema.Schema getOutputSchema(org.apache.pig.impl.logicalLayer.schema.Schema input)

Description copied from class: AliasableEvalFunc

Specify the output schema as in {link EvalFunc#outputSchema(Schema)}.

Specified by:

getOutputSchema in class AliasableEvalFunc<org.apache.pig.data.DataBag>

Returns:

outputSchema

exec

public org.apache.pig.data.DataBag exec(org.apache.pig.data.Tuple input)
                                 throws java.io.IOException

Specified by:

exec in class org.apache.pig.EvalFunc<org.apache.pig.data.DataBag>

Throws:

java.io.IOException