"""BIDS compatible path functionality."""
# Authors: Adam Li <adam2392@gmail.com>
# Stefan Appelhoff <stefan.appelhoff@mailbox.org>
#
# License: BSD (3-clause)
import glob
import os
import re
from io import StringIO
import shutil as sh
from collections import OrderedDict
from copy import deepcopy
from os import path as op
from pathlib import Path
from datetime import datetime
import json
from typing import Optional
import numpy as np
from mne.utils import warn, logger, _validate_type
from mne_bids.config import (
ALLOWED_PATH_ENTITIES, ALLOWED_FILENAME_EXTENSIONS,
ALLOWED_FILENAME_SUFFIX, ALLOWED_PATH_ENTITIES_SHORT,
ALLOWED_DATATYPES, SUFFIX_TO_DATATYPE, ALLOWED_DATATYPE_EXTENSIONS,
ALLOWED_SPACES,
reader, ENTITY_VALUE_TYPE)
from mne_bids.utils import (_check_key_val, _check_empty_room_basename,
param_regex, _ensure_tuple)
def _find_matched_empty_room(bids_path):
"""Get matching empty-room file for an MEG recording."""
# Check whether we have a BIDS root.
bids_root = bids_path.root
if bids_root is None:
raise ValueError('The root of the "bids_path" must be set. '
'Please use `bids_path.update(root="<root>")` '
'to set the root of the BIDS folder to read.')
from mne_bids import read_raw_bids # avoid circular import.
bids_path = bids_path.copy()
datatype = 'meg' # We're only concerned about MEG data here
bids_fname = bids_path.update(suffix=datatype,
root=bids_root).fpath
_, ext = _parse_ext(bids_fname)
raw = read_raw_bids(bids_path=bids_path)
if raw.info['meas_date'] is None:
raise ValueError('The provided recording does not have a measurement '
'date set. Cannot get matching empty-room file.')
ref_date = raw.info['meas_date']
if not isinstance(ref_date, datetime): # pragma: no cover
# for MNE < v0.20
ref_date = datetime.fromtimestamp(raw.info['meas_date'][0])
emptyroom_dir = BIDSPath(root=bids_root, subject='emptyroom').directory
if not emptyroom_dir.exists():
return None
# Find the empty-room recording sessions.
emptyroom_session_dirs = [x for x in emptyroom_dir.iterdir()
if x.is_dir() and str(x.name).startswith('ses-')]
if not emptyroom_session_dirs: # No session sub-directories found
emptyroom_session_dirs = [emptyroom_dir]
# Now try to discover all recordings inside the session directories.
allowed_extensions = list(reader.keys())
# `.pdf` is just a "virtual" extension for BTi data (which is stored inside
# a dedicated directory that doesn't have an extension)
del allowed_extensions[allowed_extensions.index('.pdf')]
candidate_er_fnames = []
for session_dir in emptyroom_session_dirs:
dir_contents = glob.glob(op.join(session_dir, datatype,
f'sub-emptyroom_*_{datatype}*'))
for item in dir_contents:
item = Path(item)
if ((item.suffix in allowed_extensions) or
(not item.suffix and item.is_dir())): # Hopefully BTi?
candidate_er_fnames.append(item.name)
# Walk through recordings, trying to extract the recording date:
# First, from the filename; and if that fails, from `info['meas_date']`.
best_er_bids_path = None
min_delta_t = np.inf
date_tie = False
failed_to_get_er_date_count = 0
for er_fname in candidate_er_fnames:
params = get_entities_from_fname(er_fname)
er_meas_date = None
params.pop('subject') # er subject entity is different
er_bids_path = BIDSPath(subject='emptyroom', **params, datatype='meg',
root=bids_root, check=False)
# Try to extract date from filename.
if params['session'] is not None:
try:
er_meas_date = datetime.strptime(params['session'], '%Y%m%d')
except (ValueError, TypeError):
# There is a session in the filename, but it doesn't encode a
# valid date.
pass
if er_meas_date is None: # No luck so far! Check info['meas_date']
_, ext = _parse_ext(er_fname)
extra_params = None
if ext == '.fif':
extra_params = dict(allow_maxshield=True)
er_raw = read_raw_bids(bids_path=er_bids_path,
extra_params=extra_params)
er_meas_date = er_raw.info['meas_date']
if er_meas_date is None: # There's nothing we can do.
failed_to_get_er_date_count += 1
continue
er_meas_date = er_meas_date.replace(tzinfo=ref_date.tzinfo)
delta_t = er_meas_date - ref_date
if abs(delta_t.total_seconds()) == min_delta_t:
date_tie = True
elif abs(delta_t.total_seconds()) < min_delta_t:
min_delta_t = abs(delta_t.total_seconds())
best_er_bids_path = er_bids_path
date_tie = False
if failed_to_get_er_date_count > 0:
msg = (f'Could not retrieve the empty-room measurement date from '
f'a total of {failed_to_get_er_date_count} recording(s).')
warn(msg)
if date_tie:
msg = ('Found more than one matching empty-room measurement with the '
'same recording date. Selecting the first match.')
warn(msg)
return best_er_bids_path
[docs]class BIDSPath(object):
"""A BIDS path object.
BIDS filename prefixes have one or more pieces of metadata in them. They
must follow a particular order, which is followed by this function. This
will generate the *prefix* for a BIDS filename that can be used with many
subsequent files, or you may also give a suffix that will then complete
the file name.
BIDSPath allows dynamic updating of its entities in place, and operates
similar to `pathlib.Path`. In addition, it can query multiple paths
with matching BIDS entities via the ``match`` method.
Note that not all parameters are applicable to each suffix of data. For
example, electrode location TSV files do not need a "task" field.
Parameters
----------
subject : str | None
The subject ID. Corresponds to "sub".
session : str | None
The acquisition session. Corresponds to "ses".
task : str | None
The experimental task. Corresponds to "task".
acquisition: str | None
The acquisition parameters. Corresponds to "acq".
run : int | None
The run number. Corresponds to "run".
processing : str | None
The processing label. Corresponds to "proc".
recording : str | None
The recording name. Corresponds to "rec".
space : str | None
The coordinate space for anatomical and sensor location
files (e.g., ``*_electrodes.tsv``, ``*_markers.mrk``).
Corresponds to "space".
Note that valid values for ``space`` must come from a list
of BIDS keywords as described in the BIDS specification.
split : int | None
The split of the continuous recording file for ``.fif`` data.
Corresponds to "split".
suffix : str | None
The filename suffix. This is the entity after the
last ``_`` before the extension. E.g., ``'channels'``.
The following filename suffix's are accepted:
'meg', 'markers', 'eeg', 'ieeg', 'T1w',
'participants', 'scans', 'electrodes', 'coordsystem',
'channels', 'events', 'headshape', 'digitizer',
'beh', 'physio', 'stim'
extension : str | None
The extension of the filename. E.g., ``'.json'``.
datatype : str
The BIDS data type, e.g., ``'anat'``, ``'func'``, ``'eeg'``, ``'meg'``,
``'ieeg'``.
root : str | pathlib.Path | None
The root directory of the BIDS dataset.
check : bool
If ``True``, enforces BIDS conformity. Defaults to ``True``.
Attributes
----------
entities : dict
The dictionary of the BIDS entities and their values:
``subject``, ``session``, ``task``, ``acquisition``,
``run``, ``processing``, ``space``, ``recording``, ``split``,
``suffix``, and ``extension``.
datatype : str | None
The data type, i.e., one of ``'meg'``, ``'eeg'``, ``'ieeg'``,
``'anat'``.
basename : str
The basename of the file path. Similar to `os.path.basename(fpath)`.
root : pathlib.Path
The root of the BIDS path.
directory : pathlib.Path
The directory path.
fpath : pathlib.Path
The full file path.
check : bool
Whether to enforce BIDS conformity.
Examples
--------
Generate a BIDSPath object and inspect it
>>> bids_path = BIDSPath(subject='test', session='two', task='mytask',
... suffix='ieeg', extension='.edf')
>>> print(bids_path.basename)
sub-test_ses-two_task-mytask_ieeg.edf
>>> bids_path
BIDSPath(
root: None
datatype: ieeg
basename: sub-test_ses-two_task-mytask_ieeg.edf)
Copy and update multiple entities at once
>>> new_bids_path = bids_path.copy().update(subject='test2',
... session='one')
>>> print(new_bids_path.basename)
sub-test2_ses-one_task-mytask_ieeg.edf
Printing a BIDSPath will show a relative path when `root` is not set
>>> print(new_bids_path)
sub-test2/ses-one/ieeg/sub-test2_ses-one_task-mytask_ieeg.edf
Setting `suffix` without an identifiable datatype will make
BIDSPath try to guess the datatype
>>> new_bids_path = new_bids_path.update(suffix='channels',
... extension='.tsv')
>>> print(new_bids_path)
sub-test2/ses-one/ieeg/sub-test2_ses-one_task-mytask_channels.tsv
You can set a new root for the BIDS dataset. Let's see what the
different properties look like for our object:
>>> new_bids_path = new_bids_path.update(root='/bids_dataset')
>>> print(new_bids_path.root.as_posix())
/bids_dataset
>>> print(new_bids_path.basename)
sub-test2_ses-one_task-mytask_channels.tsv
>>> print(new_bids_path)
/bids_dataset/sub-test2/ses-one/ieeg/sub-test2_ses-one_task-mytask_channels.tsv
>>> print(new_bids_path.directory.as_posix())
/bids_dataset/sub-test2/ses-one/ieeg
Notes
-----
BIDS entities are generally separated with a ``"_"`` character, while
entity key/value pairs are separated with a ``"-"`` character.
There are checks performed to make sure that there are no ``'-'``, ``'_'``,
or ``'/'`` characters contained in any entity keys or values.
To represent a filename such as ``dataset_description.json``,
one can set ``check=False``, and pass ``suffix='dataset_description'``
and ``extension='.json'``.
``BIDSPath`` can also be used to represent file and folder names of data
types that are not yet supported through MNE-BIDS, but are recognized by
BIDS. For example, one can set ``datatype`` to ``dwi`` or ``func`` and
pass ``check=False`` to represent diffusion-weighted imaging and
functional MRI paths.
"""
def __init__(self, subject=None, session=None,
task=None, acquisition=None, run=None, processing=None,
recording=None, space=None, split=None, root=None,
suffix=None, extension=None, datatype=None, check=True):
if all(ii is None for ii in [subject, session, task,
acquisition, run, processing,
recording, space, root, suffix,
extension]):
raise ValueError("At least one parameter must be given.")
self.check = check
self.update(subject=subject, session=session, task=task,
acquisition=acquisition, run=run, processing=processing,
recording=recording, space=space, split=split,
root=root, datatype=datatype,
suffix=suffix, extension=extension)
@property
def entities(self):
"""Return dictionary of the BIDS entities."""
return OrderedDict([
('subject', self.subject),
('session', self.session),
('task', self.task),
('acquisition', self.acquisition),
('run', self.run),
('processing', self.processing),
('space', self.space),
('recording', self.recording),
('split', self.split)
])
@property
def basename(self):
"""Path basename."""
basename = []
for key, val in self.entities.items():
if val is not None and key != 'datatype':
# convert certain keys to shorthand
long_to_short_entity = {
val: key for key, val
in ALLOWED_PATH_ENTITIES_SHORT.items()
}
key = long_to_short_entity[key]
basename.append(f'{key}-{val}')
if self.suffix is not None:
if self.extension is not None:
basename.append(f'{self.suffix}{self.extension}')
else:
basename.append(self.suffix)
basename = '_'.join(basename)
return basename
@property
def directory(self):
"""Get the BIDS parent directory.
If ``subject``, ``session`` and ``datatype`` are set, then they will be
used to construct the directory location. For example, if
``subject='01'``, ``session='02'`` and ``datatype='ieeg'``, then the
directory would be::
<root>/sub-01/ses-02/ieeg
Returns
-------
data_path : pathlib.Path
The path of the BIDS directory.
"""
# Create the data path based on the available entities:
# root, subject, session, and datatype
data_path = '' if self.root is None else self.root
if self.subject is not None:
data_path = op.join(data_path, f'sub-{self.subject}')
if self.session is not None:
data_path = op.join(data_path, f'ses-{self.session}')
# datatype will allow 'meg', 'eeg', 'ieeg', 'anat'
if self.datatype is not None:
data_path = op.join(data_path, self.datatype)
return Path(data_path)
@property
def subject(self) -> Optional[str]:
"""The subject ID."""
return self._subject
@subject.setter
def subject(self, value):
self.update(subject=value)
@property
def session(self) -> Optional[str]:
"""The acquisition session."""
return self._session
@session.setter
def session(self, value):
self.update(session=value)
@property
def task(self) -> Optional[str]:
"""The experimental task."""
return self._task
@task.setter
def task(self, value):
self.update(task=value)
@property
def run(self) -> Optional[str]:
"""The run number."""
return self._run
@run.setter
def run(self, value):
self.update(run=value)
@property
def acquisition(self) -> Optional[str]:
"""The acquisition parameters."""
return self._acquisition
@acquisition.setter
def acquisition(self, value):
self.update(acquisition=value)
@property
def processing(self) -> Optional[str]:
"""The processing label."""
return self._processing
@processing.setter
def processing(self, value):
self.update(processing=value)
@property
def recording(self) -> Optional[str]:
"""The recording name."""
return self._recording
@recording.setter
def recording(self, value):
self.update(recording=value)
@property
def space(self) -> Optional[str]:
"""The coordinate space for an anatomical or sensor position file."""
return self._space
@space.setter
def space(self, value):
self.update(space=value)
@property
def suffix(self) -> Optional[str]:
"""The filename suffix."""
return self._suffix
@suffix.setter
def suffix(self, value):
self.update(suffix=value)
@property
def root(self) -> Optional[Path]:
"""The root directory of the BIDS dataset."""
return self._root
@root.setter
def root(self, value):
self.update(root=value)
@property
def datatype(self) -> Optional[str]:
"""The BIDS data type, e.g. ``'anat'``, ``'meg'``, ``'eeg'``."""
return self._datatype
@datatype.setter
def datatype(self, value):
self.update(datatype=value)
@property
def split(self) -> Optional[str]:
"""The split of the continuous recording file for ``.fif`` data."""
return self._split
@split.setter
def split(self, value):
self.update(split=value)
@property
def extension(self) -> Optional[str]:
"""The extension of the filename, including a leading period."""
return self._extension
@extension.setter
def extension(self, value):
self.update(extension=value)
def __str__(self):
"""Return the string representation of the path."""
return str(self.fpath.as_posix())
def __repr__(self):
"""Representation in the style of `pathlib.Path`."""
root = self.root.as_posix() if self.root is not None else None
return f'{self.__class__.__name__}(\n' \
f'root: {root}\n' \
f'datatype: {self.datatype}\n' \
f'basename: {self.basename})'
def __fspath__(self):
"""Return the string representation for any fs functions."""
return str(self.fpath)
def __eq__(self, other):
"""Compare str representations."""
return str(self) == str(other)
def __ne__(self, other):
"""Compare str representations."""
return str(self) != str(other)
[docs] def copy(self):
"""Copy the instance.
Returns
-------
bidspath : mne_bids.BIDSPath
The copied bidspath.
"""
return deepcopy(self)
[docs] def mkdir(self, exist_ok=True):
"""Create the directory structure of the BIDS path.
Parameters
----------
exist_ok : bool
If ``False``, raise an exception if the directory already exists.
Otherwise, do nothing (default).
Returns
-------
self : mne_bids.BIDSPath
The BIDSPath object.
"""
self.directory.mkdir(parents=True, exist_ok=exist_ok)
return self
@property
def fpath(self):
"""Full filepath for this BIDS file.
Getting the file path consists of the entities passed in
and will get the relative (or full if ``root`` is passed)
path.
Returns
-------
bids_fpath : pathlib.Path
Either the relative, or full path to the dataset.
"""
# get the inner-most BIDS directory for this file path
data_path = self.directory
# account for MEG data that are directory-based
# else, all other file paths attempt to match
if self.suffix == 'meg' and self.extension == '.ds':
bids_fpath = op.join(data_path, self.basename)
elif self.suffix == 'meg' and self.extension == '.pdf':
bids_fpath = op.join(data_path,
op.splitext(self.basename)[0])
else:
# if suffix and/or extension is missing, and root is
# not None, then BIDSPath will infer the dataset
# else, return the relative path with the basename
if (self.suffix is None or self.extension is None) and \
self.root is not None:
# get matching BIDS paths inside the bids root
matching_paths = \
_get_matching_bidspaths_from_filesystem(self)
# FIXME This will break
# FIXME e.g. with FIFF data split across multiple files.
# if extension is not specified and no unique file path
# return filepath of the actual dataset for MEG/EEG/iEEG data
if self.suffix is None or self.suffix in ALLOWED_DATATYPES:
# now only use valid datatype extension
valid_exts = sum(ALLOWED_DATATYPE_EXTENSIONS.values(), [])
matching_paths = [p for p in matching_paths
if _parse_ext(p)[1] in valid_exts]
if (self.split is None and
(not matching_paths or
'_split-' in matching_paths[0])):
# try finding FIF split files (only first one)
this_self = self.copy().update(split='01')
matching_paths = \
_get_matching_bidspaths_from_filesystem(this_self)
# found no matching paths
if not matching_paths:
msg = (f'Could not locate a data file of a supported '
f'format. This is likely a problem with your '
f'BIDS dataset. Please run the BIDS validator '
f'on your data. (root={self.root}, '
f'basename={self.basename}). '
f'{matching_paths}')
warn(msg)
bids_fpath = op.join(data_path, self.basename)
# if paths still cannot be resolved, then there is an error
elif len(matching_paths) > 1:
msg = ('Found more than one matching data file for the '
'requested recording. Cannot proceed due to the '
'ambiguity. This is likely a problem with your '
'BIDS dataset. Please run the BIDS validator on '
'your data.')
raise RuntimeError(msg)
else:
bids_fpath = matching_paths[0]
else:
bids_fpath = op.join(data_path, self.basename)
bids_fpath = Path(bids_fpath)
return bids_fpath
[docs] def update(self, *, check=None, **kwargs):
"""Update inplace BIDS entity key/value pairs in object.
``run`` and ``split`` are auto-parsed to have two
numbers when passed in. For example, if ``run=1``, then it will
become ``run='01'``.
Also performs error checks on various entities to
adhere to the BIDS specification. Specifically:
- ``datatype`` should be one of: ``anat``, ``eeg``, ``ieeg``, ``meg``
- ``extension`` should be one of the accepted file
extensions in the file path: ``.con``, ``.sqd``, ``.fif``,
``.pdf``, ``.ds``, ``.vhdr``, ``.edf``, ``.bdf``, ``.set``,
``.edf``, ``.set``, ``.mef``, ``.nwb``
- ``suffix`` should be one of the acceptable file suffixes in: ``meg``,
``markers``, ``eeg``, ``ieeg``, ``T1w``,
``participants``, ``scans``, ``electrodes``, ``channels``,
``coordsystem``, ``events``, ``headshape``, ``digitizer``,
``beh``, ``physio``, ``stim``
- Depending on the modality of the data (EEG, MEG, iEEG),
``space`` should be a valid string according to Appendix VIII
in the BIDS specification.
Parameters
----------
check : None | bool
If a boolean, controls whether to enforce BIDS conformity. This
will set the ``.check`` attribute accordingly. If ``None``, rely on
the existing ``.check`` attribute instead, which is set upon
`mne_bids.BIDSPath` instantiation. Defaults to ``None``.
**kwargs : dict
It can contain updates for valid BIDS path entities:
'subject', 'session', 'task', 'acquisition', 'processing', 'run',
'recording', 'space', 'suffix', 'split', 'extension',
or updates for 'root' or 'datatype'.
Returns
-------
bidspath : mne_bids.BIDSPath
The updated instance of BIDSPath.
Examples
--------
If one creates a bids basename using
:func:`mne_bids.BIDSPath`:
>>> bids_path = BIDSPath(subject='test', session='two',
... task='mytask', suffix='channels',
... extension='.tsv')
>>> print(bids_path.basename)
sub-test_ses-two_task-mytask_channels.tsv
>>> # Then, one can update this `BIDSPath` object in place
>>> bids_path = bids_path.update(acquisition='test', suffix='ieeg',
... extension='.vhdr', task=None)
>>> print(bids_path.basename)
sub-test_ses-two_acq-test_ieeg.vhdr
"""
# Update .check attribute
if check is not None:
self.check = check
for key, val in kwargs.items():
if key == 'root':
_validate_type(val, types=('path-like', None), item_name=key)
continue
if key == 'datatype':
if val is not None and val not in ALLOWED_DATATYPES \
and self.check:
raise ValueError(f'datatype ({val}) is not valid. '
f'Should be one of '
f'{ALLOWED_DATATYPES}')
else:
continue
if key not in ENTITY_VALUE_TYPE:
raise ValueError(f'Key must be one of '
f'{ALLOWED_PATH_ENTITIES}, got {key}')
if ENTITY_VALUE_TYPE[key] == 'label':
_validate_type(val, types=(None, str),
item_name=key)
else:
assert ENTITY_VALUE_TYPE[key] == 'index'
_validate_type(val, types=(int, str, None), item_name=key)
if isinstance(val, str) and not val.isdigit():
raise ValueError(f'{key} is not an index (Got {val})')
elif isinstance(val, int):
kwargs[key] = '{:02}'.format(val)
# ensure extension starts with a '.'
extension = kwargs.get('extension')
if extension is not None:
if not extension.startswith('.'):
kwargs['extension'] = f'.{extension}'
# error check entities
for key, val in kwargs.items():
# check if there are any characters not allowed
if val is not None and key != 'root':
if key == 'suffix' and not self.check:
# suffix may skip a check if check=False to allow
# things like "dataset_description.json"
pass
else:
_check_key_val(key, val)
# set entity value, ensuring `root` is a Path
if val is not None and key == 'root':
val = Path(val).expanduser()
setattr(self, f'_{key}', val)
# infer datatype if suffix is uniquely the datatype
if self.datatype is None and \
self.suffix in SUFFIX_TO_DATATYPE:
self._datatype = SUFFIX_TO_DATATYPE[self.suffix]
# Perform a check of the entities.
self._check()
return self
[docs] def match(self, check=False):
"""Get a list of all matching paths in the root directory.
Performs a recursive search, starting in ``.root`` (if set), based on
`BIDSPath.entities` object. Ignores ``.json`` files.
Parameters
----------
check : bool
If ``True``, only returns paths that conform to BIDS. If ``False``
(default), the ``.check`` attribute of the returned
`mne_bids.BIDSPath` object will be set to ``True`` for paths that
do conform to BIDS, and to ``False`` for those that don't.
Returns
-------
bids_paths : list of mne_bids.BIDSPath
The matching paths.
"""
if self.root is None:
raise RuntimeError('Cannot match basenames if `root` '
'attribute is not set. Please set the'
'BIDS root directory path to `root` via '
'BIDSPath.update().')
# allow searching by datatype
# all other entities are filtered below
if self.datatype is not None:
search_str = f'*/{self.datatype}/*'
else:
search_str = '*.*'
fnames = self.root.rglob(search_str)
# Only keep files (not directories), and omit the JSON sidecars.
fnames = [f.name for f in fnames
if f.is_file() and f.suffix != '.json']
fnames = _filter_fnames(fnames, suffix=self.suffix,
extension=self.extension,
**self.entities)
bids_paths = []
for fname in fnames:
# get all BIDS entities from the filename
entities = get_entities_from_fname(fname)
# extension is not an entity, so get it explicitly
_, extension = _parse_ext(fname, verbose=False)
# get datatype
fpath = list(self.root.rglob(f'*{fname}*'))[0]
datatype = _infer_datatype_from_path(fpath)
# to check whether the BIDSPath is conforming to BIDS if
# check=True, we first instantiate without checking and then run
# the check manually, allowing us to be more specific about the
# exception to catch
bids_path = BIDSPath(root=self.root, datatype=datatype,
extension=extension, check=False,
**entities)
bids_path.check = True
try:
bids_path._check()
except ValueError:
# path is not BIDS-compatible
if check: # skip!
continue
else:
bids_path.check = False
bids_paths.append(bids_path)
return bids_paths
def _check(self):
"""Deep check or not of the instance."""
self.basename # run basename to check validity of arguments
# perform error check on scans
if (self.suffix == 'scans' and self.extension == '.tsv') \
and _check_non_sub_ses_entity(self):
raise ValueError('scans.tsv file name can only contain '
'subject and session entities. BIDSPath '
f'currently contains {self.entities}.')
# perform deeper check if user has it turned on
if self.check:
if self.subject == 'emptyroom':
_check_empty_room_basename(self)
# ensure extension starts with a '.'
extension = self.extension
if extension is not None:
# check validity of the extension
if extension not in ALLOWED_FILENAME_EXTENSIONS:
raise ValueError(f'Extension {extension} is not '
f'allowed. Use one of these extensions '
f'{ALLOWED_FILENAME_EXTENSIONS}.')
# labels from space entity must come from list (appendix VIII)
space = self.space
if space is not None:
datatype = getattr(self, 'datatype', None)
if datatype is None:
raise ValueError('You must define datatype if you want to '
'use space in your BIDSPath.')
allowed_spaces_for_dtype = ALLOWED_SPACES.get(datatype, None)
if allowed_spaces_for_dtype is None:
raise ValueError(f'space entity is not valid for datatype '
f'{self.datatype}')
elif space not in allowed_spaces_for_dtype:
raise ValueError(f'space ({space}) is not valid for '
f'datatype ({self.datatype}).\n'
f'Should be one of '
f'{allowed_spaces_for_dtype}')
else:
pass
# error check suffix
suffix = self.suffix
if suffix is not None and \
suffix not in ALLOWED_FILENAME_SUFFIX:
raise ValueError(f'Suffix {suffix} is not allowed. '
f'Use one of these suffixes '
f'{ALLOWED_FILENAME_SUFFIX}.')
[docs] def find_empty_room(self):
"""Find the corresponding empty-room file of an MEG recording.
This will only work if the ``.root`` attribute of the
:class:`mne_bids.BIDSPath` instance has been set.
.. note:: If the sidecar JSON file contains an ``AssociatedEmptyRoom``
entry, the empty-room recording specified there will be used.
Otherwise, this method will try to find the best-matching
empty-room recording based on measurement date.
Returns
-------
BIDSPath | None
The path corresponding to the best-matching empty-room measurement.
Returns ``None`` if none was found.
"""
if self.datatype not in ('meg', None):
raise ValueError('Empty-room data is only supported for MEG '
'datasets')
if self.root is None:
raise ValueError('The root of the "bids_path" must be set. '
'Please use `bids_path.update(root="<root>")` '
'to set the root of the BIDS folder to read.')
sidecar_fname = _find_matching_sidecar(self, extension='.json')
with open(sidecar_fname, 'r', encoding='utf-8') as f:
sidecar_json = json.load(f)
if 'AssociatedEmptyRoom' in sidecar_json:
logger.info('Using "AssociatedEmptyRoom" entry from MEG sidecar '
'file to retrieve empty-room path.')
emptytoom_path = sidecar_json['AssociatedEmptyRoom']
emptyroom_entities = get_entities_from_fname(emptytoom_path)
er_bids_path = BIDSPath(root=self.root, datatype='meg',
**emptyroom_entities)
else:
logger.info(
'The MEG sidecar file does not contain an '
'"AssociatedEmptyRoom" entry. Will try to find a matching '
'empty-room recording based on the measurement date …'
)
er_bids_path = _find_matched_empty_room(self)
if er_bids_path is not None:
assert er_bids_path.fpath.exists()
return er_bids_path
@property
def meg_calibration_fpath(self):
"""Find the matching Elekta/Neuromag/MEGIN fine-calibration file.
This requires that at least ``root`` and ``subject`` are set, and that
``datatype`` is either ``'meg'`` or ``None``.
Returns
-------
path : pathlib.Path | None
The path of the fine-calibration file, or ``None`` if it couldn't
be found.
"""
if self.root is None or self.subject is None:
raise ValueError('root and subject must be set.')
if self.datatype not in (None, 'meg'):
raise ValueError('Can only find fine-calibration file for MEG '
'datasets.')
path = BIDSPath(subject=self.subject, session=self.session,
acquisition='calibration', suffix='meg',
extension='.dat', datatype='meg', root=self.root).fpath
if not path.exists():
path = None
return path
@property
def meg_crosstalk_fpath(self):
"""Find the matching Elekta/Neuromag/MEGIN crosstalk file.
This requires that at least ``root`` and ``subject`` are set, and that
``datatype`` is either ``'meg'`` or ``None``.
Returns
-------
path : pathlib.Path | None
The path of the crosstalk file, or ``None`` if it couldn't be
found.
"""
if self.root is None or self.subject is None:
raise ValueError('root and subject must be set.')
if self.datatype not in (None, 'meg'):
raise ValueError('Can only find crosstalk file for MEG datasets.')
path = BIDSPath(subject=self.subject, session=self.session,
acquisition='crosstalk', suffix='meg',
extension='.fif', datatype='meg', root=self.root).fpath
if not path.exists():
path = None
return path
def _get_matching_bidspaths_from_filesystem(bids_path):
"""Get matching file paths for a BIDS path.
Assumes suffix and/or extension is not provided.
"""
# extract relevant entities to find filepath
sub, ses = bids_path.subject, bids_path.session
datatype = bids_path.datatype
basename, bids_root = bids_path.basename, bids_path.root
if datatype is None:
datatype = _infer_datatype(root=bids_root,
sub=sub, ses=ses)
data_dir = BIDSPath(subject=sub, session=ses, datatype=datatype,
root=bids_root).mkdir().directory
# For BTI data, just return the directory with a '.pdf' extension
# to facilitate reading in mne-bids
bti_dir = op.join(data_dir, f'{basename}')
if op.isdir(bti_dir):
logger.info(f'Assuming BTi data in {bti_dir}')
matching_paths = [f'{bti_dir}.pdf']
# otherwise, search for valid file paths
else:
search_str = bids_root
# parse down the BIDS directory structure
if sub is not None:
search_str = op.join(search_str, f'sub-{sub}')
if ses is not None:
search_str = op.join(search_str, f'ses-{ses}')
if datatype is not None:
search_str = op.join(search_str, datatype)
else:
search_str = op.join(search_str, '**')
search_str = op.join(search_str, f'{basename}*')
# Find all matching files in all supported formats.
valid_exts = ALLOWED_FILENAME_EXTENSIONS
matching_paths = glob.glob(search_str)
matching_paths = [p for p in matching_paths
if _parse_ext(p)[1] in valid_exts]
return matching_paths
def _check_non_sub_ses_entity(bids_path):
"""Check existence of non subject/session entities in BIDSPath."""
if bids_path.task or bids_path.acquisition or \
bids_path.run or bids_path.space or \
bids_path.recording or bids_path.split or \
bids_path.processing:
return True
return False
[docs]def print_dir_tree(folder, max_depth=None, return_str=False):
"""Recursively print a directory tree.
Parameters
----------
folder : str | pathlib.Path
The folder for which to print the directory tree.
max_depth : int
The maximum depth into which to descend recursively for printing
the directory tree.
return_str : bool
If ``True``, return the directory tree as a str instead of
printing it.
Returns
-------
str | None
If `return_str` is ``True``, the directory tree is returned as a
str. Else, ``None`` is returned and the directory tree is printed.
"""
if not op.exists(folder):
raise ValueError('Directory does not exist: {}'.format(folder))
msg = '`max_depth` must be a positive integer or None'
if not isinstance(max_depth, (int, type(None))):
raise ValueError(msg)
if max_depth is None:
max_depth = float('inf')
if max_depth < 0:
raise ValueError(msg)
if not isinstance(return_str, bool):
raise ValueError('`return_str` must be either True or False.')
outfile = None
if return_str is True:
outfile = StringIO()
# Use max_depth same as the -L param in the unix `tree` command
max_depth += 1
# Base length of a tree branch, to normalize each tree's start to 0
baselen = len(str(folder).split(os.sep)) - 1
# Recursively walk through all directories
for root, dirs, files in os.walk(folder, topdown=True):
# Since we're using `topdown=True`, sorting `dirs` ensures that
# `os.walk` will continue walking through directories in alphabetical
# order. So although we're not actually using `dirs` anywhere below,
# sorting it here is imperative to ensure the correct (alphabetical)
# directory sort order in the output.
dirs.sort()
files.sort()
# Check how far we have walked
branchlen = len(root.split(os.sep)) - baselen
# Only print if this is up to the depth we asked
if branchlen <= max_depth:
if branchlen <= 1:
print('|{}'.format(op.basename(root) + os.sep), file=outfile)
else:
print('|{} {}'.format((branchlen - 1) * '---',
op.basename(root) + os.sep),
file=outfile)
# Only print files if we are NOT yet up to max_depth or beyond
if branchlen < max_depth:
for file in files:
print('|{} {}'.format(branchlen * '---', file),
file=outfile)
if outfile is not None:
return outfile.getvalue()
def _parse_ext(raw_fname, verbose=False):
"""Split a filename into its name and extension."""
raw_fname = str(raw_fname)
fname, ext = os.path.splitext(raw_fname)
# BTi data is the only file format that does not have a file extension
if ext == '' or 'c,rf' in fname:
if verbose is True:
print('Found no extension for raw file, assuming "BTi" format and '
'appending extension .pdf')
ext = '.pdf'
# If ending on .gz, check whether it is an .nii.gz file
elif ext == '.gz' and raw_fname.endswith('.nii.gz'):
ext = '.nii.gz'
fname = fname[:-4] # cut off the .nii
return fname, ext
def _infer_datatype_from_path(fname):
# get the parent
datatype = Path(fname).parent.name
if any([datatype.startswith(entity) for entity in ['sub', 'ses']]):
datatype = None
if not datatype:
datatype = None
return datatype
[docs]def get_entities_from_fname(fname, on_error='raise'):
"""Retrieve a dictionary of BIDS entities from a filename.
Entities not present in ``fname`` will be assigned the value of ``None``.
Parameters
----------
fname : mne_bids.BIDSPath | str
The path to parse.
on_error : 'raise' | 'warn' | 'ignore'
If any unsupported labels in the filename are found and this is set
to ``'raise'``, raise a ``RuntimeError``. If ``'warn'``,
emit a warning and continue, and if ``'ignore'``,
neither raise an exception nor a warning, and
return all entities found. For example, currently MNE-BIDS does not
support derivatives yet, but the ``desc`` entity label is used to
differentiate different derivatives and will work with this function
if ``on_error='ignore'``.
Returns
-------
params : dict
A dictionary with the keys corresponding to the BIDS entity names, and
the values to the entity values encoded in the filename.
Examples
--------
>>> fname = 'sub-01_ses-exp_run-02_meg.fif'
>>> get_entities_from_fname(fname)
{'subject': '01', \
'session': 'exp', \
'task': None, \
'acquisition': None, \
'run': '02', \
'processing': None, \
'space': None, \
'recording': None, \
'split': None, \
'suffix': 'meg'}
"""
if on_error not in ('warn', 'raise', 'ignore'):
raise ValueError(f'Acceptable values for on_error are: warn, raise, '
f'ignore, but got: {on_error}')
fname = str(fname) # to accept also BIDSPath or Path instances
# filename keywords to the BIDS entity mapping
entity_vals = list(ALLOWED_PATH_ENTITIES_SHORT.values())
fname_vals = list(ALLOWED_PATH_ENTITIES_SHORT.keys())
params = {key: None for key in entity_vals}
idx_key = 0
for match in re.finditer(param_regex, op.basename(fname)):
key, value = match.groups()
if on_error in ('raise', 'warn'):
if key not in fname_vals:
msg = (f'Unexpected entity "{key}" found in '
f'filename "{fname}"')
if on_error == 'raise':
raise KeyError(msg)
elif on_error == 'warn':
warn(msg)
continue
if fname_vals.index(key) < idx_key:
msg = (f'Entities in filename not ordered correctly.'
f' "{key}" should have occurred earlier in the '
f'filename "{fname}"')
raise ValueError(msg)
idx_key = fname_vals.index(key)
key_short_hand = ALLOWED_PATH_ENTITIES_SHORT.get(key, key)
params[key_short_hand] = value
# parse suffix last
last_entity = fname.split('-')[-1]
if '_' in last_entity:
suffix = last_entity.split('_')[-1]
suffix, _ = _get_bids_suffix_and_ext(suffix)
params['suffix'] = suffix
return params
def _find_matching_sidecar(bids_path, suffix=None,
extension=None, on_error='raise'):
"""Try to find a sidecar file with a given suffix for a data file.
Parameters
----------
bids_path : mne_bids.BIDSPath
Full name of the data file
suffix : str | None
The filename suffix. This is the entity after the last ``_``
before the extension. E.g., ``'ieeg'``.
extension : str | None
The extension of the filename. E.g., ``'.json'``.
on_error : 'raise' | 'warn' | 'ignore'
If no matching sidecar file was found and this is set to ``'raise'``,
raise a ``RuntimeError``. If ``'warn'``, emit a warning, and if
``'ignore'``, neither raise an exception nor a warning, and return
``None`` in both cases.
Returns
-------
sidecar_fname : str | None
Path to the identified sidecar file, or ``None`` if none could be found
and ``on_error`` was set to ``'warn'`` or ``'ignore'``.
"""
if on_error not in ('warn', 'raise', 'ignore'):
raise ValueError(f'Acceptable values for on_error are: warn, raise, '
f'ignore, but got: {on_error}')
bids_root = bids_path.root
# search suffix is BIDS-suffix and extension
search_suffix = ''
if suffix is not None:
search_suffix = search_suffix + suffix
# do not search for suffix if suffix is explicitly passed
bids_path = bids_path.copy()
bids_path.check = False
bids_path.update(suffix=None)
if extension is not None:
search_suffix = search_suffix + extension
# do not search for extension if extension is explicitly passed
bids_path = bids_path.copy()
bids_path.check = False
bids_path = bids_path.update(extension=None)
# We only use subject and session as identifier, because all other
# parameters are potentially not binding for metadata sidecar files
search_str = f'sub-{bids_path.subject}'
if bids_path.session is not None:
search_str += f'_ses-{bids_path.session}'
# Find all potential sidecar files, doing a recursive glob
# from bids_root/sub_id/
search_str = op.join(bids_root, f'sub-{bids_path.subject}',
'**', search_str + '*' + search_suffix)
candidate_list = glob.glob(search_str, recursive=True)
best_candidates = _find_best_candidates(bids_path.entities,
candidate_list)
if len(best_candidates) == 1:
# Success
return best_candidates[0]
# We failed. Construct a helpful error message.
# If this was expected, simply return None, otherwise, raise an exception.
msg = None
if len(best_candidates) == 0:
msg = (f'Did not find any {search_suffix} '
f'associated with {bids_path.basename}.')
elif len(best_candidates) > 1:
# More than one candidates were tied for best match
msg = (f'Expected to find a single {suffix} file '
f'associated with {bids_path.basename}, '
f'but found {len(candidate_list)}: "{candidate_list}".')
msg += '\n\nThe search_str was "{}"'.format(search_str)
if on_error == 'raise':
raise RuntimeError(msg)
elif on_error == 'warn':
warn(msg)
return None
def _get_bids_suffix_and_ext(str_suffix):
"""Parse suffix for valid suffix and ext."""
# no matter what the suffix is, suffix and extension are last
suffix = str_suffix
ext = None
if '.' in str_suffix:
# handle case of multiple '.' in extension
split_str = str_suffix.split('.')
suffix = split_str[0]
ext = '.'.join(split_str[1:])
return suffix, ext
[docs]def get_datatypes(root):
"""Get list of data types ("modalities") present in a BIDS dataset.
Parameters
----------
root : str | pathlib.Path
Path to the root of the BIDS directory.
Returns
-------
modalities : list of str
List of the data types present in the BIDS dataset pointed to by
`root`.
"""
# Take all possible data types from "entity" table
# (Appendix in BIDS spec)
# https://bids-specification.readthedocs.io/en/stable/99-appendices/04-entity-table.html # noqa
datatype_list = ('anat', 'func', 'dwi', 'fmap', 'beh',
'meg', 'eeg', 'ieeg')
datatypes = list()
for root, dirs, files in os.walk(root):
for dir in dirs:
if dir in datatype_list and dir not in datatypes:
datatypes.append(dir)
return datatypes
[docs]def get_entity_vals(root, entity_key, *, ignore_subjects='emptyroom',
ignore_sessions=None, ignore_tasks=None, ignore_runs=None,
ignore_processings=None, ignore_spaces=None,
ignore_acquisitions=None, ignore_splits=None,
ignore_modalities=None, ignore_datatypes=None,
with_key=False):
"""Get list of values associated with an `entity_key` in a BIDS dataset.
BIDS file names are organized by key-value pairs called "entities" [1]_.
With this function, you can get all values for an entity indexed by its
key.
Parameters
----------
root : str | pathlib.Path
Path to the "root" directory from which to start traversing to gather
BIDS entities from file- and folder names. This will commonly be the
BIDS root, but it may also be a subdirectory inside of a BIDS dataset,
e.g., the ``sub-X`` directory of a hypothetical subject ``X``.
.. note:: This function searches the names of all files and directories
nested within ``root``. Depending on the size of your
dataset and storage system, searching the entire BIDS dataset
may take a **considerable** amount of time (seconds up to
several minutes). If you find yourself running into such
performance issues, consider limiting the search to only a
subdirectory in the dataset, e.g., to a single subject or
session only.
entity_key : str
The name of the entity key to search for.
ignore_subjects : str | iterable | None
Subject(s) to ignore. By default, entities from the ``emptyroom``
mock-subject are not returned. If ``None``, include all subjects.
ignore_sessions : str | iterable | None
Session(s) to ignore. If ``None``, include all sessions.
ignore_tasks : str | iterable | None
Task(s) to ignore. If ``None``, include all tasks.
ignore_runs : str | iterable | None
Run(s) to ignore. If ``None``, include all runs.
ignore_processings : str | iterable | None
Processing(s) to ignore. If ``None``, include all processings.
ignore_spaces : str | iterable | None
Space(s) to ignore. If ``None``, include all spaces.
ignore_acquisitions : str | iterable | None
Acquisition(s) to ignore. If ``None``, include all acquisitions.
ignore_splits : str | iterable | None
Split(s) to ignore. If ``None``, include all splits.
ignore_modalities : str | iterable | None
Modalities(s) to ignore. If ``None``, include all modalities.
ignore_datatypes : str | iterable | None
Datatype(s) to ignore. If ``None``, include all datatypes (i.e.
``anat``, ``ieeg``, ``eeg``, ``meg``, ``func``, etc.)
with_key : bool
If ``True``, returns the full entity with the key and the value. This
will for example look like ``['sub-001', 'sub-002']``.
If ``False`` (default), just returns the entity values. This
will for example look like ``['001', '002']``.
Returns
-------
entity_vals : list of str
List of the values associated with an `entity_key` in the BIDS dataset
pointed to by `root`.
Examples
--------
>>> root = Path('./mne_bids/tests/data/tiny_bids').absolute()
>>> entity_key = 'subject'
>>> get_entity_vals(root, entity_key)
['01']
>>> get_entity_vals(root, entity_key, with_key=True)
['sub-01']
Notes
-----
This function will scan the entire ``root``, except for a
``derivatives`` subfolder placed directly under ``root``.
References
----------
.. [1] https://bids-specification.rtfd.io/en/latest/02-common-principles.html#file-name-structure # noqa: E501
"""
entities = ('subject', 'task', 'session', 'run', 'processing', 'space',
'acquisition', 'split', 'suffix')
entities_abbr = ('sub', 'task', 'ses', 'run', 'proc', 'space', 'acq',
'split', 'suffix')
entity_long_abbr_map = dict(zip(entities, entities_abbr))
if entity_key not in entities:
raise ValueError(f'`key` must be one of: {", ".join(entities)}. '
f'Got: {entity_key}')
ignore_subjects = _ensure_tuple(ignore_subjects)
ignore_sessions = _ensure_tuple(ignore_sessions)
ignore_tasks = _ensure_tuple(ignore_tasks)
ignore_runs = _ensure_tuple(ignore_runs)
ignore_processings = _ensure_tuple(ignore_processings)
ignore_spaces = _ensure_tuple(ignore_spaces)
ignore_acquisitions = _ensure_tuple(ignore_acquisitions)
ignore_splits = _ensure_tuple(ignore_splits)
ignore_modalities = _ensure_tuple(ignore_modalities)
p = re.compile(r'{}-(.*?)_'.format(entity_long_abbr_map[entity_key]))
values = list()
filenames = (Path(root)
.rglob(f'*{entity_long_abbr_map[entity_key]}-*_*'))
for filename in filenames:
# Ignore `derivatives` folder.
if str(filename).startswith(op.join(root, 'derivatives')):
continue
if ignore_datatypes and filename.parent.name in ignore_datatypes:
continue
if ignore_subjects and any([filename.stem.startswith(f'sub-{s}_')
for s in ignore_subjects]):
continue
if ignore_sessions and any([f'_ses-{s}_' in filename.stem
for s in ignore_sessions]):
continue
if ignore_tasks and any([f'_task-{t}_' in filename.stem
for t in ignore_tasks]):
continue
if ignore_runs and any([f'_run-{r}_' in filename.stem
for r in ignore_runs]):
continue
if ignore_processings and any([f'_proc-{p}_' in filename.stem
for p in ignore_processings]):
continue
if ignore_spaces and any([f'_space-{s}_' in filename.stem
for s in ignore_spaces]):
continue
if ignore_acquisitions and any([f'_acq-{a}_' in filename.stem
for a in ignore_acquisitions]):
continue
if ignore_splits and any([f'_split-{s}_' in filename.stem
for s in ignore_splits]):
continue
if ignore_modalities and any([f'_{k}' in filename.stem
for k in ignore_modalities]):
continue
match = p.search(filename.stem)
value = match.group(1)
if with_key:
value = f'{entity_long_abbr_map[entity_key]}-{value}'
if value not in values:
values.append(value)
return sorted(values)
def _mkdir_p(path, overwrite=False, verbose=False):
"""Create a directory, making parent directories as needed [1].
References
----------
.. [1] stackoverflow.com/questions/600268/mkdir-p-functionality-in-python
"""
if overwrite and op.isdir(path):
sh.rmtree(path)
if verbose is True:
print(f'Clearing path: {path}')
os.makedirs(path, exist_ok=True)
if verbose is True:
print(f'Creating folder: {path}')
def _find_best_candidates(params, candidate_list):
"""Return the best candidate, based on the number of param matches.
Assign each candidate a score, based on how many entities are shared with
the ones supplied in the `params` parameter. The candidate with the highest
score wins. Candidates with entities that conflict with the supplied
`params` are disqualified.
Parameters
----------
params : dict
The entities that the candidate should match.
candidate_list : list of str
A list of candidate filenames.
Returns
-------
best_candidates : list of str
A list of all the candidate filenames that are tied for first place.
Hopefully, the list will have a length of one.
"""
params = {key: value for key, value in params.items() if value is not None}
best_candidates = []
best_n_matches = 0
for candidate in candidate_list:
n_matches = 0
candidate_disqualified = False
candidate_params = get_entities_from_fname(candidate)
for entity, value in params.items():
if entity in candidate_params:
if candidate_params[entity] is None:
continue
elif candidate_params[entity] == value:
n_matches += 1
else:
# Incompatible entity found, candidate is disqualified
candidate_disqualified = True
break
if not candidate_disqualified:
if n_matches > best_n_matches:
best_n_matches = n_matches
best_candidates = [candidate]
elif n_matches == best_n_matches:
best_candidates.append(candidate)
return best_candidates
def _get_datatypes_for_sub(*, root, sub, ses=None):
"""Retrieve data modalities for a specific subject and session."""
subject_dir = op.join(root, f'sub-{sub}')
if ses is not None:
subject_dir = op.join(subject_dir, f'ses-{ses}')
# TODO We do this to ensure we don't accidentally pick up any "spurious"
# TODO sub-directories. But is that really necessary with valid BIDS data?
modalities_in_dataset = get_datatypes(root=root)
subdirs = [f.name for f in os.scandir(subject_dir) if f.is_dir()]
available_modalities = [s for s in subdirs if s in modalities_in_dataset]
return available_modalities
def _infer_datatype(*, root, sub, ses):
# Check which suffix is available for this particular
# subject & session. If we get no or multiple hits, throw an error.
modalities = _get_datatypes_for_sub(root=root, sub=sub,
ses=ses)
# We only want to handle electrophysiological data here.
allowed_recording_modalities = ['meg', 'eeg', 'ieeg']
modalities = list(set(modalities) & set(allowed_recording_modalities))
if not modalities:
raise ValueError('No electrophysiological data found.')
elif len(modalities) >= 2:
msg = (f'Found data of more than one recording datatype. Please '
f'pass the `suffix` parameter to specify which data to load. '
f'Found the following modalitiess: {modalities}')
raise RuntimeError(msg)
assert len(modalities) == 1
return modalities[0]
def _path_to_str(var):
"""Make sure var is a string or Path, return string representation."""
if not isinstance(var, (Path, str)):
raise ValueError(f"All path parameters must be either strings or "
f"pathlib.Path objects. Found type {type(var)}.")
else:
return str(var)
def _filter_fnames(fnames, *, subject=None, session=None, task=None,
acquisition=None, run=None, processing=None, recording=None,
space=None, split=None, suffix=None, extension=None):
"""Filter a list of BIDS filenames based on BIDS entity values.
Parameters
----------
fnames : iterable of pathlib.Path | iterable of str
Returns
-------
list of pathlib.Path
"""
sub_str = f'sub-{subject}' if subject else r'sub-([^_]+)'
ses_str = f'_ses-{session}' if session else r'(|_ses-([^_]+))'
task_str = f'_task-{task}' if task else r'(|_task-([^_]+))'
acq_str = f'_acq-{acquisition}' if acquisition else r'(|_acq-([^_]+))'
run_str = f'_run-{run}' if run else r'(|_run-([^_]+))'
proc_str = f'_proc-{processing}' if processing else r'(|_proc-([^_]+))'
rec_str = f'_rec-{recording}' if recording else r'(|_rec-([^_]+))'
space_str = f'_space-{space}' if space else r'(|_space-([^_]+))'
split_str = f'_split-{split}' if split else r'(|_split-([^_]+))'
suffix_str = (f'_{suffix}' if suffix
else r'_(' + '|'.join(ALLOWED_FILENAME_SUFFIX) + ')')
ext_str = extension if extension else r'.([^_]+)'
regexp = (sub_str + ses_str + task_str + acq_str + run_str + proc_str +
rec_str + space_str + split_str + suffix_str + ext_str)
# Convert to str so we can apply the regexp ...
fnames = [str(f) for f in fnames]
# https://stackoverflow.com/a/51246151/1944216
fnames_filtered = sorted(filter(re.compile(regexp).match, fnames))
# ... and return Paths.
fnames_filtered = [Path(f) for f in fnames_filtered]
return fnames_filtered