[Solved-1 Solution] How to concatenate all items in Pig ?
What is concat()
- The CONCAT() function of Pig Latin is used to concatenate two or more expressions of the same type.
Syntax
grunt> CONCAT (expression, expression, [...expression])
Problem:
How to concatenate all items in Pig ?
Solution 1:
- By using python UDF we can easily achieve this
Here is a code
#!/usr/bin/python
@outputSchema('concated: string')
def concat_bag(BAG):
return '|'.join([ str(i) for i in BAG ])
- It can be used as the following:
Register 'myudfs.py' using jython as myfuncs;
-- Schema of A is: A:{ T:(letter: chararray, B_of_nums: {num: int}) }
B = FOREACH A GENERATE TOTUPLE(T.letter, myfuncs.concat_bag(T.B_of_nums)) ;
-- The output should be:
-- (A, 1|2|3)
-- (B, 1|2|3)