count()

Returns the number of rows that match the query criteria.

For example, to calculate the number of carriers:

1q = foreach q generate 'carrier' as 'carrier', count() as 'count';

count() operates on the stream that is input to the group or cogroup statement. It doesn’t operate on the newly grouped stream or on an ungrouped stream.

1q = load "Carriers";
2q = group q by (Year);
3q = foreach a1 generate count(q) as countYear, count() as count, Year as year;