Create JSONL with Python

Question

I can't figure out how to create JSONL using Python3.

test = [{'a': 'b'}, {'a': 'b'}, {'a': 'b'}]

with open("data.json", 'w') as f:
    for item in test:
        json.dump(item, f)

with open("data.json") as f:
    for line in f:
        // only 1 line here! 
        print(line)

// prints
{"a": "b"}{"a": "b"}{"a": "b"}

I've tried using indent option to dump but it appears to make no different and the separators option don't seem to be a great usecase. Not sure what I'm missing here?

Do you want each item in test as a new line in the output file? — Rakesh, Jul 17 '19 at 09:03

score 23 · Accepted Answer · answered Jul 17 '19 at 09:09

23

Use .write with newline \n

Ex:

import json
test = [{'a': 'b'}, {'a': 'b'}, {'a': 'b'}]

with open("data.json", 'w') as f:
    for item in test:
        f.write(json.dumps(item) + "\n")

with open("data.json") as f:
    for line in f:
        print(line)

answered Jul 17 '19 at 09:09

Rakesh

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1

You're right, was overthinking it - that does seem to be valid JSONL. Thanks – rix Jul 17 '19 at 09:31
You can also use jsonlines, or ndjson :) – Ido Bleicher Sep 06 '22 at 14:47

Create JSONL with Python

1 Answers1