def agg_dict_like(
obj: AggObjType,
arg: AggFuncTypeDict,
_axis: int,
) -> FrameOrSeriesUnion:
"""
Compute aggregation in the case of a dict-like argument.
Parameters
----------
obj : Pandas object to compute aggregation on.
arg : dict
label-aggregation pairs to compute.
_axis : int, 0 or 1
Axis to compute aggregation on.
Returns
-------
Result of aggregation.
"""
is_aggregator = lambda x: isinstance(x, (list, tuple, dict))
if _axis != 0: # pragma: no cover
raise ValueError("Can only pass dict with axis=0")
selected_obj = obj._selected_obj
# if we have a dict of any non-scalars
# eg. {'A' : ['mean']}, normalize all to
# be list-likes
if any(is_aggregator(x) for x in arg.values()):
new_arg: AggFuncTypeDict = {}
for k, v in arg.items():
if not isinstance(v, (tuple, list, dict)):
new_arg[k] = [v]
else:
new_arg[k] = v
# the keys must be in the columns
# for ndim=2, or renamers for ndim=1
# ok for now, but deprecated
# {'A': { 'ra': 'mean' }}
# {'A': { 'ra': ['mean'] }}
# {'ra': ['mean']}
# not ok
# {'ra' : { 'A' : 'mean' }}
if isinstance(v, dict):
raise SpecificationError("nested renamer is not supported")
elif isinstance(selected_obj, ABCSeries):
raise SpecificationError("nested renamer is not supported")
elif (
isinstance(selected_obj, ABCDataFrame) and k not in selected_obj.columns
):
raise KeyError(f"Column '{k}' does not exist!")
arg = new_arg
else:
# deprecation of renaming keys
# GH 15931
keys = list(arg.keys())
if isinstance(selected_obj, ABCDataFrame) and len(
selected_obj.columns.intersection(keys)
) != len(keys):
cols = sorted(set(keys) - set(selected_obj.columns.intersection(keys)))
raise SpecificationError(f"Column(s) {cols} do not exist")
from pandas.core.reshape.concat import concat
if selected_obj.ndim == 1:
# key only used for output
colg = obj._gotitem(obj._selection, ndim=1)
results = {key: colg.agg(how) for key, how in arg.items()}
else:
# key used for column selection and output
results = {key: obj._gotitem(key, ndim=1).agg(how) for key, how in arg.items()}
# set the final keys
keys = list(arg.keys())
# Avoid making two isinstance calls in all and any below
is_ndframe = [isinstance(r, ABCNDFrame) for r in results.values()]
# combine results
if all(is_ndframe):
keys_to_use = [k for k in keys if not results[k].empty]
# Have to check, if at least one DataFrame is not empty.
keys_to_use = keys_to_use if keys_to_use != [] else keys
axis = 0 if isinstance(obj, ABCSeries) else 1
result = concat({k: results[k] for k in keys_to_use}, axis=axis)
elif any(is_ndframe):
# There is a mix of NDFrames and scalars
raise ValueError(
"cannot perform both aggregation "
"and transformation operations "
"simultaneously"
)
else:
from pandas import Series
# we have a dict of scalars
# GH 36212 use name only if obj is a series
if obj.ndim == 1:
obj = cast("Series", obj)
name = obj.name
else:
name = None
result = Series(results, name=name)
return result
def agg_list_like(
obj: AggObjType,
arg: List[AggFuncTypeBase],
_axis: int,
) -> FrameOrSeriesUnion:
"""
Compute aggregation in the case of a list-like argument.
Parameters
----------
obj : Pandas object to compute aggregation on.
arg : list
Aggregations to compute.
_axis : int, 0 or 1
Axis to compute aggregation on.
Returns
-------
Result of aggregation.
"""
from pandas.core.reshape.concat import concat
if _axis != 0:
raise NotImplementedError("axis other than 0 is not supported")
if obj._selected_obj.ndim == 1:
selected_obj = obj._selected_obj
else:
selected_obj = obj._obj_with_exclusions
results = []
keys = []
# degenerate case
if selected_obj.ndim == 1:
for a in arg:
colg = obj._gotitem(selected_obj.name, ndim=1, subset=selected_obj)
try:
new_res = colg.aggregate(a)
except TypeError:
pass
else:
results.append(new_res)
# make sure we find a good name
name = com.get_callable_name(a) or a
keys.append(name)
# multiples
else:
for index, col in enumerate(selected_obj):
colg = obj._gotitem(col, ndim=1, subset=selected_obj.iloc[:, index])
try:
new_res = colg.aggregate(arg)
except (TypeError, DataError):
pass
except ValueError as err:
# cannot aggregate
if "Must produce aggregated value" in str(err):
# raised directly in _aggregate_named
pass
elif "no results" in str(err):
# raised directly in _aggregate_multiple_funcs
pass
else:
raise
else:
results.append(new_res)
keys.append(col)
# if we are empty
if not len(results):
raise ValueError("no results")
try:
return concat(results, keys=keys, axis=1, sort=False)
except TypeError as err:
# we are concatting non-NDFrame objects,
# e.g. a list of scalars
from pandas import Series
result = Series(results, index=keys, name=obj.name)
if is_nested_object(result):
raise ValueError(
"cannot combine transform and aggregation operations"
) from err
return result
