Sorry, but late back but I’ve just found the code.
It’s a bit of a weird case where I needed to reverse arrays inside a big json blob (millions of big json blobs). Trying to explode the structures out and rebuild them was a bit of a no-go. Instead I did a nasty little regex replace on the json string:
re.sub('"key": \[([^\\]]+)\]', lambda match: '"key": [' + ', '.join(reversed(match.group(1).split(', '))) + "]", els)
There might be a way of doing this in postgres these days (this was 3 or 4 years ago), but I'm not sure. At the time this was the best I could come up with and I was pretty surprised it worked as well as it did.
Since then I've always installed the python extension whenever I set up a new postgres, just in case.
