在T：tuple中找不到字段

如何解决在T：tuple中找不到字段

我的数据是：

(10,1) [70#3300]
(10,2) [71#3300]
(10,1) [70#3300]
(11,1) [71#3300]
(12,1) [72#3300]
(10,3) [74#3300]

其余为：

grunt> a = LOAD '/user/maria_dev/complex_2.txt'  USING PigStorage(' ') AS (T:tuple(driverId:int,week:int),M:[mileslogged:int]);
grunt> medians = FOREACH (GROUP a ALL) GENERATE a.T;

以下命令的输出

grunt> describe medians;  

是

medians: {{(T: (driverId: int,week: int))}}

但是当我跑步

    m1 = FOREACH medians GENERATE T.driverId;

我收到以下错误：

2020-07-24 00:24:32,094 [main] ERROR org.apache.pig.tools.grunt.Grunt - ERROR 1128: Cannot find field driverId in T:tuple(driverId:int,week:int)
  Details at logfile: /home/maria_dev/pig_1595549443230.log

如何仅选择driverId？

解决方法

a = LOAD '/user/maria_dev/complex_2.txt'  USING PigStorage(' ') AS (T:tuple(driverId:int,week:int),M:[mileslogged:int]);

medians = FOREACH (GROUP a ALL) GENERATE FLATTEN(a.T) AS T:tuple(driverId:int,week:int);

driverIds = FOREACH medians GENERATE T.driverId;