# Order manufacturers by the average review ratings
from nested import product_db
import numpy as np
from pythonql.helpers import print_table
res = [ select (make, avg_stars)
for p in product_db
# We extract the manufacturer with the try-except
# pattern
let make = try p['manufacturer']['company'] except p['manufacturer'],
# For the stars, we simply filter out all reviews that don't
# contain stars
rev_stars = [ select r['stars']
for r in p['reviews']
where 'stars' in r ]
group by make
# Unnest the stars into a single list
let stars = [select x for r in rev_stars, x in r],
avg_stars = np.mean(stars)
order by avg_stars desc
]
print_table(res)
