refactor: AttributeValueList now uses a NumPy array as its backing store

Author: ntamas

src/igraph_ctypes/_internal/attributes/enums.py

@@ -0,0 +1,3 @@
+from ..enums import AttributeType
+
+__all__ = ("AttributeType",)

src/igraph_ctypes/_internal/attributes/utils.py

@@ -0,0 +1,86 @@
+import numpy as np
+
+from numpy.typing import DTypeLike
+from typing import Any, Iterable
+
+from .enums import AttributeType
+from ..types import (
+    np_type_of_igraph_bool_t,
+    np_type_of_igraph_real_t,
+)
+
+__all__ = (
+    "get_igraph_attribute_type_from_iterable",
+    "get_numpy_attribute_type_from_iterable",
+    "igraph_to_numpy_attribute_type",
+)
+
+
+def get_igraph_attribute_type_from_iterable(  # noqa: C901
+    it: Iterable[Any],
+) -> AttributeType:
+    """Determines the appropriate igraph attribute type to store all the items
+    found in the given iterable as an attribute.
+
+    When the iterable is empty, the returned attribute type will be unspecified.
+    """
+    it = iter(it)
+    try:
+        item = next(it)
+    except StopIteration:
+        # Iterable empty
+        return AttributeType.UNSPECIFIED
+
+    best_fit: AttributeType
+    if isinstance(item, bool):
+        best_fit = AttributeType.BOOLEAN
+    elif isinstance(item, (int, float, np.number)):
+        best_fit = AttributeType.NUMERIC
+    elif isinstance(item, str):
+        best_fit = AttributeType.STRING
+    else:
+        return AttributeType.OBJECT
+
+    for item in it:
+        if isinstance(item, bool):
+            if best_fit == AttributeType.STRING:
+                return AttributeType.OBJECT
+        elif isinstance(item, (int, float, np.number)):
+            if best_fit == AttributeType.STRING:
+                return AttributeType.OBJECT
+            else:
+                best_fit = AttributeType.NUMERIC
+        elif isinstance(item, str):
+            if best_fit != AttributeType.STRING:
+                return AttributeType.OBJECT
+        else:
+            return AttributeType.OBJECT
+
+    return best_fit
+
+
+def get_numpy_attribute_type_from_iterable(
+    it: Iterable[Any],
+) -> DTypeLike:
+    """Determines the appropriate NumPy attribute type to store all the items
+    found in the given iterable as an attribute.
+
+    This is done by first determining the corresponding igraph attribute type,
+    and mapping that type to a NumPy type.
+
+    When the iterable is empty, a numeric attribute will be assumed.
+    """
+    attr_type = get_igraph_attribute_type_from_iterable(it)
+    if attr_type is AttributeType.UNSPECIFIED:
+        attr_type = AttributeType.NUMERIC
+    return igraph_to_numpy_attribute_type(attr_type)
+
+
+def igraph_to_numpy_attribute_type(type: AttributeType) -> DTypeLike:
+    """Converts an igraph attribute type to an equivalent NumPy data type."""
+    if type is AttributeType.BOOLEAN:
+        return np_type_of_igraph_bool_t
+    elif type is AttributeType.NUMERIC:
+        return np_type_of_igraph_real_t
+    else:
+        return np.object_