change default behaviour of from_file and read methods

src/py21cmfast/_utils.py

@@ -1135,7 +1135,7 @@ def read(
  self,
  direc: Union[str, Path, None] = None,
  fname: Union[str, Path, None, h5py.File, h5py.Group] = None,
- keys: Optional[Sequence[str]] = None,
+ keys: Optional[Sequence[str]] = [],
  ):
  """
  Try find and read existing boxes from cache, which match the parameters of this instance.
@@ -1149,15 +1149,17 @@ def read(
  The filename to read. By default, use the filename associated with this
  object. Can be an open h5py File or Group, which will be directly written to.
  keys
- The names of boxes to read in (can be a subset). By default, read everything.
+ The names of boxes to read in (can be a subset). By default, read nothing.
+ If `None` is explicitly passed, read everything
  """
  if not isinstance(fname, (h5py.File, h5py.Group)):
  pth = self._get_path(direc, fname)
  fl = h5py.File(pth, "r")
  else:
  fl = fname
 
- keys = keys or []
+ if keys is None:
+ keys = self._array_structure
  try:
  try:
  boxes = fl[self._name]
@@ -1214,9 +1216,8 @@ def from_file(
  cls,
  fname,
  direc=None,
- load_data=True,
  h5_group: Union[str, None] = None,
- arrays_to_load=None,
+ arrays_to_load=[],
  ):
  """Create an instance from a file on disk.
 
@@ -1227,12 +1228,13 @@ def from_file(
  direc : str, optional
  The directory from which fname is relative to (if it is relative). By
  default, will be the cache directory in config.
- load_data : bool, optional
- Whether to read in the data when creating the instance. If False, a bare
- instance is created with input parameters -- the instance can read data
- with the :func:`read` method.
  h5_group
  The path to the group within the file in which the object is stored.
+ arrays_to_load : list of str, optional
+ A list of array names to load into memory
+ If the list is empty (default), a bare instance is created with input parameters
+ -- the instance can read data with the :func:`read` method.
+ If `None` is explicitly passed, all arrays are loaded into memory
  """
  direc = path.expanduser(direc or config["direc"])
 
@@ -1245,9 +1247,6 @@ def from_file(
  else:
  self = cls(**cls._read_inputs(fl))
 
- if not load_data:
- arrays_to_load = []
-
  if h5_group is not None:
  with h5py.File(fname, "r") as fl:
  self.read(fname=fl[h5_group], keys=arrays_to_load)