Pig Bag & Tuple Functions#
Function | Description |
---|---|
TOBAG() | To convert two or more expressions into a bag. |
TOP() | To get the top N tuples of a relation. |
TOTUPLE() | To convert one or more expressions into a tuple. |
TOMAP() | To convert the key-value pairs into a Map. |
TOBAG()#
TOBAG(expression [, expression ...])
grunt> emp_data = LOAD 'hdfs://localhost:9000/pig_data/employee_details.txt' USING PigStorage(',')
as (id:int, name:chararray, age:int, city:chararray);
grunt> tobag = FOREACH emp_data GENERATE TOBAG (id,name,age,city);
grunt> DUMP tobag;
TOP()#
grunt> TOP(topN,column,relation)
grunt> emp_data = LOAD 'hdfs://localhost:9000/pig_data/employee_details.txt' USING PigStorage(',')
as (id:int, name:chararray, age:int, city:chararray);
grunt> emp_group = Group emp_data BY age;
grunt> Dump emp_group;
grunt> data_top = FOREACH emp_group {
top = TOP(2, 0, emp_data);
GENERATE top;
}
grunt> Dump data_top;
TOTUPLE()#
grunt> TOTUPLE(expression [, expression ...])
grunt> emp_data = LOAD 'hdfs://localhost:9000/pig_data/employee_details.txt' USING PigStorage(',')
as (id:int, name:chararray, age:int, city:chararray);
grunt> totuple = FOREACH emp_data GENERATE TOTUPLE (id,name,age);
grunt> DUMP totuple;
TOMAP()#
grunt> TOMAP(key-expression, value-expression [, key-expression, valueexpression ...])
grunt> emp_data = LOAD 'hdfs://localhost:9000/pig_data/employee_details.txt' USING PigStorage(',')
as (id:int, name:chararray, age:int, city:chararray);
grunt> tomap = FOREACH emp_data GENERATE TOMAP(name, age);
grunt> DUMP tomap;