Data_files not working with custom loading script and remote dataset

Hi! I have a small test public dataset here (trajectories from reinforcement learning agent): Howuhh/nle_hf_dataset at main

It has simple structure with two directories. Metadata which is just a json file for each episode and data which is hdf5 file for each episode.

Thus, metadata/*.json and data/*.hdf5.
I wrote a custom script to load it into the dataset. I don’t want to load all the files as the final dataset will be big, so I tried to load only some part with data_files option. It works locally, when I call it like that:

load_dataset("", "metadata", data_files=["metadata/1.json", "metadata/2.json"])

It will load only needed files. However, when I try to load from the repo, it fails:

load_dataset("Howuhh/nle_hf_dataset", "metadata", data_files=["metadata/1.json", "metadata/2.json"])

with strange error:

FileNotFoundError                         Traceback (most recent call last)
Cell In [36], line 1
----> 1 load_dataset("Howuhh/nle_hf_dataset", "metadata", data_files=["metadata/1.json", "metadata/2.json"])

File ~/miniconda3/envs/jax/lib/python3.9/site-packages/datasets/, in load_dataset(path, name, data_dir, data_files, split, cache_dir, features, download_config, download_mode, verification_mode, ignore_verifications, keep_in_memory, save_infos, revision, use_auth_token, task, streaming, num_proc, storage_options, **config_kwargs)
   1768 verification_mode = VerificationMode(
   1769     (verification_mode or VerificationMode.BASIC_CHECKS) if not save_infos else VerificationMode.ALL_CHECKS
   1770 )
   1772 # Create a dataset builder
-> 1773 builder_instance = load_dataset_builder(
   1774     path=path,
   1775     name=name,
   1776     data_dir=data_dir,
   1777     data_files=data_files,
   1778     cache_dir=cache_dir,
   1779     features=features,
   1780     download_config=download_config,
   1781     download_mode=download_mode,
   1782     revision=revision,
   1783     use_auth_token=use_auth_token,
   1784     storage_options=storage_options,
   1785     **config_kwargs,
   1786 )
   1788 # Return iterable dataset in case of streaming
   1789 if streaming:

File ~/miniconda3/envs/jax/lib/python3.9/site-packages/datasets/, in load_dataset_builder(path, name, data_dir, data_files, cache_dir, features, download_config, download_mode, revision, use_auth_token, storage_options, **config_kwargs)
   1525     raise ValueError(error_msg)
   1527 # Instantiate the dataset builder
-> 1528 builder_instance: DatasetBuilder = builder_cls(
   1529     cache_dir=cache_dir,
   1530     config_name=config_name,
   1531     data_dir=data_dir,
   1532     data_files=data_files,
   1533     hash=hash,
   1534     features=features,
   1535     use_auth_token=use_auth_token,
   1536     storage_options=storage_options,
   1537     **builder_kwargs,
   1538     **config_kwargs,
   1539 )
   1541 return builder_instance

File ~/miniconda3/envs/jax/lib/python3.9/site-packages/datasets/, in DatasetBuilder.__init__(self, cache_dir, config_name, hash, base_path, info, features, use_auth_token, repo_id, data_files, data_dir, storage_options, writer_batch_size, name, **config_kwargs)
    326 self._writer_batch_size = writer_batch_size or self.DEFAULT_WRITER_BATCH_SIZE
    328 if data_files is not None and not isinstance(data_files, DataFilesDict):
--> 329     data_files = DataFilesDict.from_local_or_remote(
    330         sanitize_patterns(data_files), base_path=base_path, use_auth_token=use_auth_token
    331     )
    333 # Prepare config: DatasetConfig contains name, version and description but can be extended by each dataset
    334 if "features" in inspect.signature(self.BUILDER_CONFIG_CLASS.__init__).parameters and features is not None:

File ~/miniconda3/envs/jax/lib/python3.9/site-packages/datasets/, in DataFilesDict.from_local_or_remote(cls, patterns, base_path, allowed_extensions, use_auth_token)
    780 out = cls()
    781 for key, patterns_for_key in patterns.items():
    782     out[key] = (
--> 783         DataFilesList.from_local_or_remote(
    784             patterns_for_key,
    785             base_path=base_path,
    786             allowed_extensions=allowed_extensions,
    787             use_auth_token=use_auth_token,
    788         )
    789         if not isinstance(patterns_for_key, DataFilesList)
    790         else patterns_for_key
    791     )
    792 return out

File ~/miniconda3/envs/jax/lib/python3.9/site-packages/datasets/, in DataFilesList.from_local_or_remote(cls, patterns, base_path, allowed_extensions, use_auth_token)
    742 @classmethod
    743 def from_local_or_remote(
    744     cls,
    748     use_auth_token: Optional[Union[bool, str]] = None,
    749 ) -> "DataFilesList":
    750     base_path = base_path if base_path is not None else str(Path().resolve())
--> 751     data_files = resolve_patterns_locally_or_by_urls(base_path, patterns, allowed_extensions)
    752     origin_metadata = _get_origin_metadata_locally_or_by_urls(data_files, use_auth_token=use_auth_token)
    753     return cls(data_files, origin_metadata)

File ~/miniconda3/envs/jax/lib/python3.9/site-packages/datasets/, in resolve_patterns_locally_or_by_urls(base_path, patterns, allowed_extensions)
    347         data_files.append(Url(pattern))
    348     else:
--> 349         for path in _resolve_single_pattern_locally(base_path, pattern, allowed_extensions):
    350             data_files.append(path)
    352 if not data_files:

File ~/miniconda3/envs/jax/lib/python3.9/site-packages/datasets/, in _resolve_single_pattern_locally(base_path, pattern, allowed_extensions)
    291     if allowed_extensions is not None:
    292         error_msg += f" with any supported extension {list(allowed_extensions)}"
--> 293     raise FileNotFoundError(error_msg)
    294 return sorted(out)

FileNotFoundError: Unable to find '' at /Users/a.p.nikulin/All/nle_hf_dataset/https:/

I don’t understand why is searching in such a strange path (and why there is https there…). As I understood from the documentation, I can specify relative paths even for the repository, not just local files.

Hi ! Indeed passing data_files is supported only if the dataset has no dataset script, of if its dataset script uses the data_files argument.

Unfortunately the Howuhh/nle_hf_dataset dataset seems to have a dataset script but it doesn’t use the data_files argument.

Still, the error message is incorrect and we should fix it. Sorry for the inconvenience.

Could you open an issue on the datasets repo about the bad error message ?

As I shared here Data files not working with custom loading script and dataset - #4 by Howuhh it will not work even if loading script uses data_files, as links will be not properly formatted

Ah yes I remember indeed, this needs to be fixed first