fix np.sctypeDict calls

Author: Mathieu Scheltienne

nibabel/casting.py

@@ -45,7 +45,22 @@ class CastingError(Exception):
     ],
     'others': [bool, object, bytes, str, np.void],
 }
-
+# fmt: off
+sctypes_named = {
+    getattr(np, dtype)
+    for dtype in (
+        'int8', 'byte', 'int16', 'short', 'int32', 'intc', 'int_', 'int64', 'longlong',
+        'uint8', 'ubyte', 'uint16', 'ushort', 'uint32', 'uintc', 'uint', 'uint64', 'ulonglong',  # noqa: E501
+        'float16', 'half', 'float32', 'single', 'float64', 'double', 'float96', 'float128', 'longdouble',  # noqa: E501
+        'complex64', 'csingle', 'complex128', 'cdouble', 'complex192', 'complex256', 'clongdouble',  # noqa: E501
+        # other names of the built-in scalar types
+        'int_', 'float_', 'complex_', 'bytes_', 'str_', 'bool_', 'datetime64', 'timedelta64',  # noqa: E501
+        # other
+        'object_', 'void',
+    )
+    if hasattr(np, dtype)
+}
+# fmt: on
 
 def float_to_int(arr, int_type, nan2zero=True, infmax=False):
     """Convert floating point array `arr` to type `int_type`

nibabel/spatialimages.py

@@ -139,6 +139,7 @@
 import numpy as np
 
 from .arrayproxy import ArrayLike
+from .casting import sctypes_named
 from .dataobj_images import DataobjImage
 from .filebasedimages import FileBasedHeader, FileBasedImage
 from .fileholders import FileMap
@@ -333,7 +334,7 @@ def _supported_np_types(klass: type[HasDtype]) -> set[type[np.generic]]:
         else:
             raise e
     supported = set()
-    for np_type in set(np.sctypeDict.values()):
+    for np_type in sctypes_named:
         try:
             obj.set_data_dtype(np_type)
         except HeaderDataError:

nibabel/tests/test_analyze.py

@@ -26,7 +26,7 @@
 from .. import imageglobals
 from ..analyze import AnalyzeHeader, AnalyzeImage
 from ..arraywriters import WriterError
-from ..casting import as_int
+from ..casting import as_int, sctypes_named
 from ..nifti1 import Nifti1Header
 from ..optpkg import optional_package
 from ..spatialimages import HeaderDataError, HeaderTypeError, supported_np_types
@@ -52,7 +52,7 @@ def add_duplicate_types(supported_np_types):
     # Update supported numpy types with named scalar types that map to the same set of dtypes
     dtypes = {np.dtype(t) for t in supported_np_types}
     supported_np_types.update(
-        scalar for scalar in set(np.sctypeDict.values()) if np.dtype(scalar) in dtypes
+        scalar for scalar in sctypes_named if np.dtype(scalar) in dtypes
     )
 
 

nibabel/tests/test_spm99analyze.py

@@ -23,7 +23,7 @@
 # files
 needs_scipy = unittest.skipUnless(have_scipy, 'scipy not available')
 
-from ..casting import shared_range, type_info
+from ..casting import sctypes_named, shared_range, type_info
 from ..spatialimages import HeaderDataError
 from ..spm99analyze import HeaderTypeError, Spm99AnalyzeHeader, Spm99AnalyzeImage
 from ..testing import (
@@ -39,7 +39,7 @@
 # For testing, we want all concrete classes of a type
 # Key on kind, rather than abstract base classes, since timedelta64 is a signedinteger
 sctypes = {}
-for sctype in set(np.sctypeDict.values()):
+for sctype in sctypes_named:
     sctypes.setdefault(np.dtype(sctype).kind, []).append(sctype)
 
 # Sort types to ensure that xdist doesn't complain about test order when we parametrize