huggingface / huggingface/datasets

Support the deserialization of json lines files comprised of lists

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#6,907 1 comment 0 reactions 1 assignee Claimed by @albertvillanova View on GitHub
enhancement
Dominant language
Python
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Description

### Feature request

I manage a somewhat large and popular Hugging Face dataset known as the [Open Australian Legal Corpus](https://huggingface.co/datasets/umarbutler/open-australian-legal-corpus). I recently updated my corpus to be stored in a json lines file where each line is an array and each element represents a value at a particular column. Previously, my corpus was stored as a json lines file where each line was a dictionary and the keys were the fields.

Essentially, a line in my json lines file used to look like this:
```json
{"version_id":"","type":"","jurisdiction":"","source":"","citation":"","url":"","when_scraped":"","text":""}
```

And now it looks like this:
```json
["","","","","","","",""]
```

This saves 65 bytes per document and allows me very quickly serialise and deserialise documents via `msgspec`.

After making this change, I found that `datasets` was incapable of deserialising my Corpus without a custom loading script, even if I ensured that the `dataset_info` field in my dataset card contained the desired names of my features.

I would like to request that functionality be added to support this format which is more memory-efficent and faster than using dictionaries.

### Motivation

The [documentation](https://huggingface.co/docs/datasets/en/dataset_script) for creating dataset loading scripts asserts that:
> In the next major release, the new safety features of 🤗 Datasets will disable running dataset loading scripts by default, and you will have to pass trust_remote_code=True to load datasets that require running a dataset script.

I would rather not require my users to pass `trust_remote_code=True` which means that I will need built-in support for this format.

### Your contribution

I would be happy to submit a PR for this if this is something you would incorporate into `datasets` and if I can be pointed to where the code would need to go.

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