zea.data.utils

Utility functions for zea datasets.

Functions

decode_file_info(file_info)	Decode file info from a json string.
json_dumps(obj)	Used to serialize objects that contain range and slice objects.
json_loads(obj)	Used to deserialize objects that contain range and slice objects.

Classes

ZeaJSONEncoder(*[, skipkeys, ensure_ascii, ...])

Wrapper for json.dumps to encode range and slice objects.

class zea.data.utils.ZeaJSONEncoder(*, skipkeys=False, ensure_ascii=True, check_circular=True, allow_nan=True, sort_keys=False, indent=None, separators=None, default=None)

Bases: JSONEncoder

Wrapper for json.dumps to encode range and slice objects.

Example

>>> import json
>>> from zea.data.utils import ZeaJSONEncoder
>>> json.dumps(range(10), cls=ZeaJSONEncoder)
'{"__type__": "range", "start": 0, "stop": 10, "step": 1}'

Note

Probably you would use the zea.data.dataloader.json_dumps() function instead of using this class directly.

Constructor for JSONEncoder, with sensible defaults.

If skipkeys is false, then it is a TypeError to attempt encoding of keys that are not str, int, float, bool or None. If skipkeys is True, such items are simply skipped.

If ensure_ascii is true, the output is guaranteed to be str objects with all incoming non-ASCII characters escaped. If ensure_ascii is false, the output can contain non-ASCII characters.

If check_circular is true, then lists, dicts, and custom encoded objects will be checked for circular references during encoding to prevent an infinite recursion (which would cause an RecursionError). Otherwise, no such check takes place.

If allow_nan is true, then NaN, Infinity, and -Infinity will be encoded as such. This behavior is not JSON specification compliant, but is consistent with most JavaScript based encoders and decoders. Otherwise, it will be a ValueError to encode such floats.

If sort_keys is true, then the output of dictionaries will be sorted by key; this is useful for regression tests to ensure that JSON serializations can be compared on a day-to-day basis.

If indent is a non-negative integer, then JSON array elements and object members will be pretty-printed with that indent level. An indent level of 0 will only insert newlines. None is the most compact representation.

If specified, separators should be an (item_separator, key_separator) tuple. The default is (’, ‘, ‘: ‘) if indent is None and (‘,’, ‘: ‘) otherwise. To get the most compact JSON representation, you should specify (‘,’, ‘:’) to eliminate whitespace.

If specified, default is a function that gets called for objects that can’t otherwise be serialized. It should return a JSON encodable version of the object or raise a TypeError.

default(o)

Implement this method in a subclass such that it returns a serializable object for o, or calls the base implementation (to raise a TypeError).

For example, to support arbitrary iterators, you could implement default like this:

def default(self, o):
    try:
        iterable = iter(o)
    except TypeError:
        pass
    else:
        return list(iterable)
    # Let the base class default method raise the TypeError
    return super().default(o)

zea.data.utils.decode_file_info(file_info)

Decode file info from a json string. A batch of H5Generator can return a list of file_info that are json strings. This function decodes the json strings and returns a list of dictionaries with the information, namely: - full_path: full path to the file - file_name: file name - indices: indices used to extract the image from the file

zea.data.utils.json_dumps(obj)

Used to serialize objects that contain range and slice objects. :type obj: :param obj: object to serialize (most likely a dictionary).

Returns:

serialized object (json string).

Return type:

str

zea.data.utils.json_loads(obj)

Used to deserialize objects that contain range and slice objects. :type obj: :param obj: object to deserialize (most likely a json string).

Returns:

deserialized object (dictionary).

Return type:

object