datafu.pig.bags
Class PrependToBag
java.lang.Object
org.apache.pig.EvalFunc<T>
datafu.pig.util.SimpleEvalFunc<org.apache.pig.data.DataBag>
datafu.pig.bags.PrependToBag
public class PrependToBag
- extends SimpleEvalFunc<org.apache.pig.data.DataBag>
Prepends a tuple to a bag.
N.B. this copies the entire input bag, so don't use it for large bags.
Example:
define PrependToBag datafu.pig.bags.PrependToBag();
-- input:
-- ({(1),(2),(3)},(4))
-- ({(10),(20),(30),(40),(50)},(60))
input = LOAD 'input' AS (B: bag{T: tuple(v:INT)}, T: tuple(v:INT));
-- output:
-- ({(4),(1),(2),(3)})
-- ({(60),(10),(20),(30),(40),(50)})
output = FOREACH input GENERATE PrependToBag(B,T) as B;
Fields inherited from class org.apache.pig.EvalFunc |
log, pigLogger, reporter, returnType |
Method Summary |
org.apache.pig.data.DataBag |
call(org.apache.pig.data.DataBag inputBag,
org.apache.pig.data.Tuple t)
|
org.apache.pig.impl.logicalLayer.schema.Schema |
outputSchema(org.apache.pig.impl.logicalLayer.schema.Schema input)
Override outputSchema so we can verify the input schema at pig compile time, instead of runtime |
Methods inherited from class org.apache.pig.EvalFunc |
finish, getArgToFuncMapping, getCacheFiles, getInputSchema, getLogger, getPigLogger, getReporter, getSchemaName, isAsynchronous, progress, setInputSchema, setPigLogger, setReporter, setUDFContextSignature, warn |
Methods inherited from class java.lang.Object |
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
PrependToBag
public PrependToBag()
call
public org.apache.pig.data.DataBag call(org.apache.pig.data.DataBag inputBag,
org.apache.pig.data.Tuple t)
throws java.io.IOException
- Throws:
java.io.IOException
outputSchema
public org.apache.pig.impl.logicalLayer.schema.Schema outputSchema(org.apache.pig.impl.logicalLayer.schema.Schema input)
- Description copied from class:
SimpleEvalFunc
- Override outputSchema so we can verify the input schema at pig compile time, instead of runtime
- Overrides:
outputSchema
in class SimpleEvalFunc<org.apache.pig.data.DataBag>
- Parameters:
input
- input schema
- Returns:
- call to super.outputSchema in case schema was defined elsewhere
Matthew Hayes, Sam Shah