namedtuples.py

from collections import namedtuple
from datetime import datetime
date_pattern = "%Y-%m-%dT%H:%M:%S.%fZ"

Point = namedtuple("Point", ("x", "y"))



def serialize_datetime(nt):
    assert hasattr(nt, '_asdict')
    d = nt._asdict()
    if "dt" not in d:
        return nt
    d["dt"] = datetime.strftime(d["dt"], date_pattern)
    return type(nt)(**d)


def deserialize_datetime(d: dict):
    assert isinstance(d, dict)
    if "dt" not in d:
        return d
    d["dt"] = datetime.strptime(d["dt"], date_pattern)
    return d


def from_dicts(lst, NamedTuple=None):
    if len(lst) == 0:
        return []
    first = lst[0]
    if NamedTuple is None:
        if "_namedtuple" in first:
            NamedTuple = locals()[first["_namedtuple"]]
            lst = [{k: v for k, v in d.items() if k in NamedTuple._fields} for d in lst]
        else:
            raise TypeError("Missing `_namedtuple` field, Cannot infer the type of the list members.")
    elif isinstance(NamedTuple, str):
        # Autoload named tuple
        NamedTuple = locals()[NamedTuple]
    if isinstance(first, NamedTuple):
        return lst
    elif isinstance(first, dict):
        return [NamedTuple(**deserialize_datetime(d)) for d in lst]
    raise TypeError("Cannot cast '{s}' to '{t}'".format(s=type(first).__name__, t=NamedTuple.__name__))


def to_dicts(lst, with_type=True):
    assert hasattr(lst, "__iter__"), "`lst` must be iterable"
    assert all([hasattr(x, '_asdict') for x in lst]), "Not all members of the list are namedtuples"
    if with_type:
        return [dict(serialize_datetime(x)._asdict(), _namedtuple=type(x).__name__) for x in lst]
    return [serialize_datetime(x)._asdict() for x in lst]