def common_dtype(arrs):
"""
Use numpy to find the common dtype for a list of ndarrays.
Only allow arrays within the following fundamental numpy data types:
``np.bool_``, ``np.object_``, ``np.number``, ``np.character``, ``np.void``
Parameters
----------
arrs : list of ndarray objects
Arrays for which to find the common dtype
Returns
-------
dtype_str : str
String representation of dytpe (dtype ``str`` attribute)
"""
def dtype(arr):
return getattr(arr, 'dtype', np.dtype('O'))
np_types = (np.bool_, np.object_, np.number, np.character, np.void)
uniq_types = set(
tuple(issubclass(dtype(arr).type, np_type) for np_type in np_types)
for arr in arrs)
if len(uniq_types) > 1:
# Embed into the exception the actual list of incompatible types.
incompat_types = [dtype(arr).name for arr in arrs]
tme = MergeConflictError(
'Arrays have incompatible types {0}'.format(incompat_types))
tme._incompat_types = incompat_types
raise tme
arrs = [np.empty(1, dtype=dtype(arr)) for arr in arrs]
# For string-type arrays need to explicitly fill in non-zero
# values or the final arr_common = .. step is unpredictable.
for i, arr in enumerate(arrs):
if arr.dtype.kind in ('S', 'U'):
arrs[i] = [(u'0' if arr.dtype.kind == 'U' else b'0') *
dtype_bytes_or_chars(arr.dtype)]
arr_common = np.array([arr[0] for arr in arrs])
return arr_common.dtype.str
def common_dtype(arrs):
"""
Use numpy to find the common dtype for a list of ndarrays.
Only allow arrays within the following fundamental numpy data types:
``np.bool_``, ``np.object_``, ``np.number``, ``np.character``, ``np.void``
Parameters
----------
arrs : list of ndarray objects
Arrays for which to find the common dtype
Returns
-------
dtype_str : str
String representation of dytpe (dtype ``str`` attribute)
"""
def dtype(arr):
return getattr(arr, 'dtype', np.dtype('O'))
np_types = (np.bool_, np.object_, np.number, np.character, np.void)
uniq_types = set(tuple(issubclass(dtype(arr).type, np_type) for np_type in np_types)
for arr in arrs)
if len(uniq_types) > 1:
# Embed into the exception the actual list of incompatible types.
incompat_types = [dtype(arr).name for arr in arrs]
tme = MergeConflictError('Arrays have incompatible types {0}'
.format(incompat_types))
tme._incompat_types = incompat_types
raise tme
arrs = [np.empty(1, dtype=dtype(arr)) for arr in arrs]
# For string-type arrays need to explicitly fill in non-zero
# values or the final arr_common = .. step is unpredictable.
for i, arr in enumerate(arrs):
if arr.dtype.kind in ('S', 'U'):
arrs[i] = [(u'0' if arr.dtype.kind == 'U' else b'0') *
dtype_bytes_or_chars(arr.dtype)]
arr_common = np.array([arr[0] for arr in arrs])
return arr_common.dtype.str
def test_dtype_bytes_or_chars():
assert misc.dtype_bytes_or_chars(np.dtype(np.float64)) == 8
assert misc.dtype_bytes_or_chars(np.dtype(object)) is None
assert misc.dtype_bytes_or_chars(np.dtype(np.int32)) == 4
assert misc.dtype_bytes_or_chars(np.array(b'12345').dtype) == 5
assert misc.dtype_bytes_or_chars(np.array('12345').dtype) == 5
def test_dtype_bytes_or_chars():
assert misc.dtype_bytes_or_chars(np.dtype(np.float64)) == 8
assert misc.dtype_bytes_or_chars(np.dtype(object)) is None
assert misc.dtype_bytes_or_chars(np.dtype(np.int32)) == 4
assert misc.dtype_bytes_or_chars(np.array(b'12345').dtype) == 5
assert misc.dtype_bytes_or_chars(np.array(u'12345').dtype) == 5
