def _infer_dtype_from_scalar(val):
""" interpret the dtype from a scalar """
dtype = np.object_
# a 1-element ndarray
if isinstance(val, np.ndarray):
if val.ndim != 0:
raise ValueError(
"invalid ndarray passed to _infer_dtype_from_scalar")
dtype = val.dtype
val = val.item()
elif isinstance(val, string_types):
# If we create an empty array using a string to infer
# the dtype, NumPy will only allocate one character per entry
# so this is kind of bad. Alternately we could use np.repeat
# instead of np.empty (but then you still don't want things
# coming out as np.str_!
dtype = np.object_
elif isinstance(val, (np.datetime64,
datetime)) and getattr(val, 'tzinfo', None) is None:
val = lib.Timestamp(val).value
dtype = np.dtype('M8[ns]')
elif isinstance(val, (np.timedelta64, timedelta)):
val = lib.Timedelta(val).value
dtype = np.dtype('m8[ns]')
elif is_bool(val):
dtype = np.bool_
elif is_integer(val):
if isinstance(val, np.integer):
dtype = type(val)
else:
dtype = np.int64
elif is_float(val):
if isinstance(val, np.floating):
dtype = type(val)
else:
dtype = np.float64
elif is_complex(val):
dtype = np.complex_
return dtype, val
def f(values, axis=None, skipna=True, **kwds):
if len(self.kwargs) > 0:
for k, v in compat.iteritems(self.kwargs):
if k not in kwds:
kwds[k] = v
try:
if self.zero_value is not None and values.size == 0:
if values.ndim == 1:
# wrap the 0's if needed
if is_timedelta64_dtype(values):
return lib.Timedelta(0)
return 0
else:
result_shape = (values.shape[:axis] +
values.shape[axis + 1:])
result = np.empty(result_shape)
result.fill(0)
return result
if (_USE_BOTTLENECK and skipna
and _bn_ok_dtype(values.dtype, bn_name)):
result = bn_func(values, axis=axis, **kwds)
# prefer to treat inf/-inf as NA, but must compute the func
# twice :(
if _has_infs(result):
result = alt(values, axis=axis, skipna=skipna, **kwds)
else:
result = alt(values, axis=axis, skipna=skipna, **kwds)
except Exception:
try:
result = alt(values, axis=axis, skipna=skipna, **kwds)
except ValueError as e:
# we want to transform an object array
# ValueError message to the more typical TypeError
# e.g. this is normally a disallowed function on
# object arrays that contain strings
if is_object_dtype(values):
raise TypeError(e)
raise
return result
def _wrap_results(result, dtype):
""" wrap our results if needed """
if is_datetime64_dtype(dtype):
if not isinstance(result, np.ndarray):
result = lib.Timestamp(result)
else:
result = result.view(dtype)
elif is_timedelta64_dtype(dtype):
if not isinstance(result, np.ndarray):
# raise if we have a timedelta64[ns] which is too large
if np.fabs(result) > _int64_max:
raise ValueError("overflow in timedelta operation")
result = lib.Timedelta(result, unit='ns')
else:
result = result.astype('i8').view(dtype)
return result
def maybe_promote(dtype, fill_value=np.nan):
# if we passed an array here, determine the fill value by dtype
if isinstance(fill_value, np.ndarray):
if issubclass(fill_value.dtype.type, (np.datetime64, np.timedelta64)):
fill_value = iNaT
else:
# we need to change to object type as our
# fill_value is of object type
if fill_value.dtype == np.object_:
dtype = np.dtype(np.object_)
fill_value = np.nan
# returns tuple of (dtype, fill_value)
if issubclass(dtype.type, (np.datetime64, np.timedelta64)):
# for now: refuse to upcast datetime64
# (this is because datetime64 will not implicitly upconvert
# to object correctly as of numpy 1.6.1)
if isna(fill_value):
fill_value = iNaT
else:
if issubclass(dtype.type, np.datetime64):
try:
fill_value = tslib.Timestamp(fill_value).value
except:
# the proper thing to do here would probably be to upcast
# to object (but numpy 1.6.1 doesn't do this properly)
fill_value = iNaT
elif issubclass(dtype.type, np.timedelta64):
try:
fill_value = lib.Timedelta(fill_value).value
except:
# as for datetimes, cannot upcast to object
fill_value = iNaT
else:
fill_value = iNaT
elif is_datetimetz(dtype):
if isna(fill_value):
fill_value = iNaT
elif is_float(fill_value):
if issubclass(dtype.type, np.bool_):
dtype = np.object_
elif issubclass(dtype.type, np.integer):
dtype = np.float64
elif is_bool(fill_value):
if not issubclass(dtype.type, np.bool_):
dtype = np.object_
elif is_integer(fill_value):
if issubclass(dtype.type, np.bool_):
dtype = np.object_
elif issubclass(dtype.type, np.integer):
# upcast to prevent overflow
arr = np.asarray(fill_value)
if arr != arr.astype(dtype):
dtype = arr.dtype
elif is_complex(fill_value):
if issubclass(dtype.type, np.bool_):
dtype = np.object_
elif issubclass(dtype.type, (np.integer, np.floating)):
dtype = np.complex128
elif fill_value is None:
if is_float_dtype(dtype) or is_complex_dtype(dtype):
fill_value = np.nan
elif is_integer_dtype(dtype):
dtype = np.float64
fill_value = np.nan
elif is_datetime_or_timedelta_dtype(dtype):
fill_value = iNaT
else:
dtype = np.object_
else:
dtype = np.object_
# in case we have a string that looked like a number
if is_categorical_dtype(dtype):
pass
elif is_datetimetz(dtype):
pass
elif issubclass(np.dtype(dtype).type, string_types):
dtype = np.object_
return dtype, fill_value