Parsing string in a hive table - sql

Question

I have a hive table which has two columns (day, type_of_day) both of type string
"monday" [{"temp" : 45, "weather": "rainny"}, {"temp" : 25, "weather": "sunny"}, {"temp" : 15, "weather": "storm"}]
"tuesday" [{"temp" : 5, "weather": "winter"}, {"temp" : 10, "weather": "sun"}, {"temp" : 18, "weather": "dawn"}]
I wanna split ( I guess explode is the technical term) and then just get a list of weather for each day. I'm familiar with how to do this in python but is there a way to directly do this in hive.
"monday" [45, 25, 15]
"tuesday" [5, 10, 18]

Answer 1

Testing with your data example. Replace CTE with your table. Read comments in the code:
with your_table as (--use your table instead of this CTE
select stack(2,
"monday",'[{"temp" : 45, "weather": "rainny"}, {"temp" : 25, "weather": "sunny"}, {"temp" : 15, "weather": "storm"}]',
"tuesday" ,'[{"temp" : 5, "weather": "winter"}, {"temp" : 10, "weather": "sun"}, {"temp" : 18, "weather": "dawn"}]'
)as (day, type_of_day)
) --use your table instead of this CTE
select s.day, array(get_json_object(type_of_day_array[0],'$.temp'),
get_json_object(type_of_day_array[1],'$.temp'),
get_json_object(type_of_day_array[2],'$.temp')
) as result_array --extract JSON elements and construct array
from
(
select day, split(regexp_replace(regexp_replace(type_of_day,'\\[|\\]',''), --remove square brackets
'\\}, *\\{','\\}##\\{'), --make convenient split separator
'##') --split
as type_of_day_array
from your_table --use your table instead of this CTE
)s;
Result:
s.day result_array
monday ["45","25","15"]
tuesday ["5","10","18"]
If the array of JSON can contain more than three elements, then you can use lateral view explode or posexplode and then build the resulting array like in this answer: https://stackoverflow.com/a/51570035/2700344.
Wrap array elements in cast(... as int) if you need array<int> as a result instead of array<string>:
cast(get_json_object(type_of_day[0],'$.temp') as int)...