filter - 过滤并更改 pig 中的列

Question

假设我的数据看起来像

row1 cats val12 val13
row2 dogs val22 val23
row3 cats val32 val33
...

data = load 'file' AS (row:chararry, pets:charray, val2:charray, val3:charray);

过滤数据以仅保存“猫”行

felines = filter data by (pets matches 'cats');

现在将“猫”更改为“狮子”

lions = foreach felines generate replace (pets, 'cats', 'lions');
dump lions;

(lions)
(lions)
...

我的目标是创建新行以添加到我的表中

newFelines = foreach lions generate rows, lions, val1, val2;
                                    Error ^^^^^
"Error during parsing. Scalars can be only used with projections"

如何获得具有以下新行的集合？

row1 lions val11 val12
row3 lions val31 val32

TIA,

Answer 1

逐行：

没有 'chararry' 或 'charray' 数据类型：

data = load 'file' USING  PigStorage(' ')  AS 
    (row:chararray, pets:chararray, val2:chararray, val3:chararray);

提取“猫”：

felines = filter data by (pets matches 'cats');

用 'lions' 替换 'cats' 可以这样完成：

lions = foreach felines generate row, REPLACE(pets, 'cats', 'lions'), val2, val3;

或者像这样：

lions = foreach felines generate row, 'lions', val2, val3;