Apache PIG - 基于另一个值创建一个新列

Question

我有一个被定义为Chararray的列（名为Product），它有三个值：OT，AT和HP。我想创建一个新的列和整数变换此值：

1. OT = 1
2. AT = 2
3. HP = 3

对于我创建一个foreach statment：

REGISTER '/usr/lib/pig/piggybank.jar'; 

File = load '/user/cloudera/file.csv' 
    USING org.apache.pig.piggybank.storage.CSVExcelStorage(',') 
     as (ID:Long, 
      Chain:Int, 
      Dept:Int, 
      Product_Measure:Chararray, 
      Price:Double); 


Values = FOREACH File Generate 
          ID, 
              Chain, 
              Dept, 
              ((Chararray)Product_Measure=='OT'?'1':(Chararray)Product_Measure=='AT'?'2':(Chararray)Product_Measure=='HP'?'3':'0') as Product_Measure, 
              (Price<0.1?0:Price) as Price; 

Filter_Values = FILTER Values BY Price > 0; 

DUMP Filter_Values; 

如果删除第三行它工作正常，所以我认为问题是当我尝试转换int的chararray。

任何人都可以帮助我吗？

谢谢！

Answer 1

Values = FOREACH Source Generate 
         ID, 
         Date, 
         ((Chararray)Product == 'OT' ? (int)1 : (Chararray)Product_Measure == 'AT' ? (int)2 : (Chararray)Product_Measure == 'HP' ? (int)3 : 0) as Product_Value, 
        (Quantity<0?0:Quantity) as Quantity, 
        (Price<0.1?0:Price) as Price; 

，或者如果你想NULL，则

Values = FOREACH Source Generate 
          ID, 
          Date, 
          ((Chararray)Product == 'OT' ? '1' : (Chararray)Product_Measure == 'AT' ? '2' : (Chararray)Product_Measure == 'HP' ? '3' : 'NULL') as Product_Value, 
         (Quantity<0?0:Quantity) as Quantity, 
         (Price<0.1?0:Price) as Price; 

两个修改u需要在你的猪脚本来执行。 月1日到位的=只是把== 2日如果u想null价值将其转换为其他chararray全部换成价值int