def invoke(obj, path, *args, **kargs):
"""Invokes the method at path of object.
Args:
obj (dict): The object to query.
path (list|str): The path of the method to invoke.
args (optional): Arguments to pass to method call.
kargs (optional): Keyword arguments to pass to method call.
Returns:
mixed: Result of the invoked method.
Example:
>>> obj = {'a': [{'b': {'c': [1, 2, 3, 4]}}]}
>>> invoke(obj, 'a[0].b.c.pop', 1)
2
>>> obj
{'a': [{'b': {'c': [1, 3, 4]}}]}
.. versionadded:: 1.0.0
"""
paths = to_path(path)
target_path = pyd.initial(paths)
method_name = pyd.last(paths)
try:
method = getattr(get(obj, target_path), method_name)
except AttributeError:
ret = None
else:
ret = method(*args, **kargs)
return ret
def update_path(obj, callback, keys, default=None):
"""Update the value of an object described by `keys` using `callback`. If
any part of the object path doesn't exist, it will be created with
`default`. The callback is invoked with the last key value of `obj`:
``(value)``
Args:
obj (list|dict): Object to modify.
callback (callable): Function that returns updated value.
keys (list): A list of string keys that describe the object path to
modify.
default (mixed, optional): Default value to assign if path part is not
set. Defaults to ``{}`` if `obj` is a ``dict`` or ``[]`` if `obj`
is a ``list``.
Returns:
mixed: Updated `obj`.
Example:
>>> update_path({}, lambda value: value, ['a', 'b'])
{'a': {'b': None}}
>>> update_path([], lambda value: value, [0, 0])
[[None]]
.. versionadded:: 2.0.0
"""
# pylint: disable=redefined-outer-name
if default is None:
default = {} if isinstance(obj, dict) else []
if not pyd.is_list(keys):
keys = [keys]
last_key = pyd.last(keys)
obj = clone_deep(obj)
target = obj
for key in pyd.initial(keys):
set_item(target, key, clone_deep(default), allow_override=False)
try:
target = target[key]
except TypeError:
target = target[int(key)]
set_item(target, last_key, callback(get_item(target,
last_key,
default=None)))
return obj
def unset(obj, path):
"""Removes the property at `path` of `obj`.
Note:
Only ``list``, ``dict``, or objects with a ``pop()`` method can be
unset by this function.
Args:
obj (mixed): The object to modify.
path (mixed): The path of the property to unset.
Returns:
bool: Whether the property was deleted.
Warning:
`obj` is modified in place.
Example:
>>> obj = {'a': [{'b': {'c': 7}}]}
>>> unset(obj, 'a[0].b.c')
True
>>> obj
{'a': [{'b': {}}]}
>>> unset(obj, 'a[0].b.c')
False
"""
tokens = to_path_tokens(path)
if not pyd.is_list(tokens): # pragma: no cover
tokens = [tokens]
last_key = pyd.last(tokens)
if isinstance(last_key, PathToken):
last_key = last_key.key
target = obj
for idx, token in enumerate(pyd.initial(tokens)):
if isinstance(token, PathToken):
key = token.key
else:
key = token
try:
try:
target = target[key]
except TypeError:
target = target[int(key)]
except Exception:
target = NoValue
if target is NoValue:
break
did_unset = False
if target is not NoValue:
try:
try:
target.pop(last_key)
did_unset = True
except TypeError:
target.pop(int(last_key))
did_unset = True
except Exception:
pass
return did_unset
def update_with(obj, path, updater, customizer=None):
"""This method is like :func:`update` except that it accepts customizer
which is invoked to produce the objects of path. If customizer returns
``None``, path creation is handled by the method instead. The customizer is
invoked with three arguments: ``(nested_value, key, nested_object)``.
Args:
obj (list|dict): Object to modify.
path (str|list): A string or list of keys that describe the object path
to modify.
updater (function): Function that returns updated value.
customizer (function, optional): The function to customize assigned
values.
Returns:
mixed: Updated `obj`.
Warning:
`obj` is modified in place.
Example:
>>> update_with({}, '[0][1]', lambda: 'a', lambda: {})
{0: {1: 'a'}}
.. versionadded:: 4.0.0
"""
if not callable(updater):
updater = pyd.constant(updater)
if customizer is not None and not callable(customizer):
call_customizer = partial(callit, clone, customizer, argcount=1)
elif customizer:
call_customizer = partial(callit, customizer,
argcount=getargcount(customizer, maxargs=3))
else:
call_customizer = None
default_type = dict if isinstance(obj, dict) else list
tokens = to_path_tokens(path)
if not pyd.is_list(tokens): # pragma: no cover
tokens = [tokens]
last_key = pyd.last(tokens)
if isinstance(last_key, PathToken):
last_key = last_key.key
target = obj
for idx, token in enumerate(pyd.initial(tokens)):
if isinstance(token, PathToken):
key = token.key
default_factory = pyd.get(tokens,
[idx + 1, 'default_factory'],
default=default_type)
else:
key = token
default_factory = default_type
obj_val = base_get(target, key, default=None)
path_obj = None
if call_customizer:
path_obj = call_customizer(obj_val, key, target)
if path_obj is None:
path_obj = default_factory()
base_set(target, key, path_obj, allow_override=False)
try:
target = target[key]
except TypeError as exc: # pragma: no cover
try:
target = target[int(key)]
_failed = False
except Exception:
_failed = True
if _failed:
raise TypeError('Unable to update object at index {!r}. {}'
.format(key, exc))
value = base_get(target, last_key, default=None)
base_set(target, last_key, callit(updater, value))
return obj
def test_initial(case, expected):
assert _.initial(case) == expected
def test_dash_method_call():
value = [1, 2, 3, 4, 5]
assert _._.initial(value) == _.initial(value)
def test_dash_method_call():
value = [1, 2, 3, 4, 5]
assert _._.initial(value) == _.initial(value)
