Prints all values from one subkey of a json file of a specific format if it includes a particular substring (used e.g. for extracting values from a json manifest)

manifest_extractor.py

__author__ = 'ptrourke'
import json

"""
Print value from one subkey `key2` in a json file of the structure below
if it includes a substring `filter_string`
'key': {
    'key2': ['value1sstring', 'value2', 'value3sstring'],
    # [...]
}

prints

'key: value1sstring, value3sstring'
"""
json_file_name = '/home/ptrourke/workspace/projectone/collections/manifest.json'
key2 = 'aka'
filter_string = 'lccn.loc.gov'
with open(json_file_name) as manifest_json:
    manifest = json.load(manifest_json)
sections = []
for key in manifest:
    key2_values = manifest[key].get(key2,[])
    filter_matches = []
    for key2_value in key2_values:
        if filter_string in key2_value:
          filter_matches.append(key2_value)
    sections.append('%s: %s' % (key, ','.join(filter_matches)))
sections = sorted(sections)
for section_item in sections:
    print(section_item)