qjoin - request - build a lookup table as a final collection #6
Description
a lookup table allows to retrieve an element of a final collection from a key. This key can only be a base collection key.
generate a lookup table from a key in the base collection
space_crafts_lookup = qjoin.on(spacecrafts)
.join(spacecrafts_properties, key='name')
.as_lookup(key='name')
space_info = space_crafts_lookup['Kepler']
print(space_info[0]['cospar_id'])construct a lookup table from an artificial key in the base collection
space_crafts_lookup = qjoin.on(spacecrafts)
.join(spacecrafts_properties, key='name')
.as_lookup(key=lambda s: s['name'])
space_info = space_crafts_lookup['Kepler']
print(space_info[0]['cospar_id'])the lookup table is made on a non-unique attribute
If the lookup table is made with a key that is not unique, the value of a non-unique key is the last element that has that value in the base collection