你不需要自定义项就可以做到这一点。假设您已将数据加载到关系a。

B = FOREACH A GENERATE A.Id,A.name,A.age,(A.age%5 == 0 ? A.age-5 : (A.age/5)*5) as lower_age,(A.age%5 == 0 ? A.age : ((A.age/5)*5) + 5) as upper_age;
C = FOREACH B GENERATE B.Id,B.name,B.age,CONCAT(CONCAT((chararray)lower_age,'-'),(chararray)upper_age);
DUMP C;

您可以在eclipse中创建pig udf
在eclipse中使用pig jars创建一个项目，并尝试以下代码

package com;
import java.io.IOException;
import org.apache.pig.EvalFunc;
import org.apache.pig.backend.executionengine.ExecException;
import org.apache.pig.data.Tuple;
public class Age extends EvalFunc<String>{
    @Override
    public String exec(Tuple a) throws IOException {
        // TODO Auto-generated method stub
        if(a == null || a.size() == 0){
            return null;
        }
        try{
            Object object = a.get(0);
            if(object == null){
                return null;
            }
            int i = (Integer) object;
            if(i >= 10 && i <= 20 ){
                return "10-20";
            }
            else if (i >= 21 && i <= 30){
                return "20-30";
            }
            else 
                return ">30";
        } catch (ExecException e){
            throw new IOException(e);
        }
    }
}

现在将项目导出为jar并在pig shell中注册

REGISTER <path of your .jar file>

用包和类来定义它。

DEFINE U com.Age();
a = LOAD '<input path>' using PigStorage(',') as (id:int,name:chararray,age:int);
b = FOREACH a GENERATE id,name,age,U(age);