Python: make a list generator JSON serializable

Question

How can I concat a list of JSON files into a huge JSON array? I\'ve 5000 files and 550 000 list items.

My fist try was to use jq, but it looks like jq -s is not opt

Answer 1

You should derive from list and override __iter__ method.

import json

def gen():
    yield 20
    yield 30
    yield 40

class StreamArray(list):
    def __iter__(self):
        return gen()

    # according to the comment below
    def __len__(self):
        return 1

a = [1,2,3]
b = StreamArray()

print(json.dumps([1,a,b]))

Result is [1, [1, 2, 3], [20, 30, 40]].