"""
This module contains helper functions for working with dictionaries.
"""
import warnings
import attr
[docs]def diff_dict(old, new):
"""
Compares old and new dictionaries, yielding for each difference (key,
old_value, new_value).
None is used for missing values.
"""
for key in sorted(old.keys() | new.keys()):
v_old = old.get(key)
v_new = new.get(key)
if v_old != v_new:
yield key, v_old, v_new
[docs]def flat_dict(d):
def flatten(d, prefix=()):
for key, value in d.items():
key = prefix + (key,)
if isinstance(value, dict):
yield from flatten(value, prefix=key)
else:
yield '.'.join(key), value
return dict(flatten(d))
[docs]def filter_dict(d, cls, warn=False):
"""
Returns a copy a dictionary which only contains the attributes defined on
an attrs class.
"""
assert attr.has(cls)
fields = set(a.name for a in attr.fields(cls))
if warn:
remove = set(d) - fields
for k in sorted(remove):
warnings.warn(
f"unsupported attribute '{k}' with value '{d[k]}' for class '{cls.__name__}'",
stacklevel=2
)
return {k: v for k, v in d.items() if k in fields}
[docs]def find_dict(d, key):
"""
Recursively search for a key in a dictionary
Args:
d (dict): The dictionary to recursively search through
key (str): The key to search for
"""
if key in d:
return d[key]
for v in d.values():
if isinstance(v, dict):
value = find_dict(v, key)
if value is not None:
return value