Pig UDF 用户自定义函数

register /xx/yy.jar
data = load ‘data‘;
result = foreach data generate aa.bb.Upper($0);
dump result;

register hdfs://pig/xx/yy.jar

data = load ‘data‘;
result = foreach data generate aa.bb.Upper($0);
dump result;

register /xx/yy.jar
define UPPER aa.bb. Upper();
data = load ‘data‘;
result = foreach data generate UPPER($0);
dump result;

register /xx/yy.jar
define UPPER1 aa.bb. Upper();
define UPPER2 aa.bb. Upper(‘abc‘);
data = load ‘data‘;
result = foreach data generate UPPER1($0), UPPER2($1);
dump result;

define hex InvokeForString(‘java.lang.Integer.toHexString‘, ‘int‘);
data = load ‘data‘;
result = foreach data generate hex((int)$0);

define stdev InvokeForDouble(‘com.acme.stats.stdev‘, ‘double[]‘);
a = load ‘data‘ as (id:int, dp:double);
b = group a by id;
c = foreach b generate stdev(a.dp);

package com.test.pig.udf;
import java.io.IOException;
import org.apache.pig.EvalFunc;
import org.apache.pig.data.Tuple;
public class CustomReplaceFunc extends EvalFunc<String> {
	@Override
	public String exec(Tuple tuple) throws IOException {
		if(tuple == null || tuple.size() == 0 || tuple.isNull(0) ) {
			return null;
		}
		
		String original = (String)tuple.get(0);
		String oldChar = (String)tuple.get(1);
		String newChar = (String)tuple.get(2);
		
		return original.replaceAll(oldChar, newChar);
	}
}

register /home/pig/myfunc.jar
define MyReplace com.test.pig.udf.CustomReplaceFunc();
users = load ‘/users.data‘ as (name:chararray, age, address);
result = foreach users generate MyReplace(name, ‘l‘, ‘L‘), age, address;
dump result;