j = {
'posts': [{
'files': ['1.jpg', '2.jpg']
}, {
'files': ['3.jpg', '4.jpg']
}, {
'files': ['5.jpg']
}]
}
print ', '.join(
[fname for cont in j['posts'] for fname in cont['files']]
)
CmogPSB7CgkncG9zdHMnOiBbewoJCSdmaWxlcyc6IFsnMS5qcGcnLCAnMi5qcGcnXQoJfSwgewoJCSdmaWxlcyc6IFsnMy5qcGcnLCAnNC5qcGcnXQoJfSwgewoJCSdmaWxlcyc6IFsnNS5qcGcnXQoJfV0KfQoKcHJpbnQgJywgJy5qb2luKAoJW2ZuYW1lIGZvciBjb250IGluIGpbJ3Bvc3RzJ10gZm9yIGZuYW1lIGluIGNvbnRbJ2ZpbGVzJ11dCikK