问题
Input file is:
2, cornflakes, Regular,General Mills, 12
3, cornflakes, Mixed Nuts, Post, 14
4, chocolate syrup, Regular, Hersheys, 5
5, chocolate syrup, No High Fructose, Hersheys, 8
6, chocolate syrup, Regular, Ghirardeli, 6
7, chocolate syrup, Strawberry Flavor, Ghirardeli, 7
filter3 = LOAD 'location_of_file' using PigStorage('\t') as (item_sl : int, item : chararray, type: chararray, manufacturer: chararray, price : int);
SPLIT filter3 INTO filter4 IF (FOREACH (filter3 GROUP BY item) GENERATE group, COUNT(item < 3)), filter6_pass OTHERWISE;
It is like having a SQL with a group by on item having count(*) < 3
The desired output is:
4, chocolate syrup, Regular, Hersheys, 5
5, chocolate syrup, No High Fructose, Hersheys, 8
6, chocolate syrup, Regular, Ghirardeli, 6
7, chocolate syrup, Strawberry Flavor, Ghirardeli, 7
回答1:
Group by item, get the count and then use filter on the count
A = LOAD 'location_of_file' using PigStorage('\t') as (item_sl : int, item : chararray, type: chararray, manufacturer: chararray, price : int);
B = GROUP A BY item;
C = FOREACH B GENERATE group,COUNT(A.item) AS Total;
D = FILTER C BY Total > 3;
E = JOIN A BY item,D BY $0;
F = FOREACH E GENERATE $0..$4;
DUMP F;
来源：https://stackoverflow.com/questions/43355010/pig-programming-to-use-split-on-group-by-having-count