Vector - Support Single-Pass Iterables

src/nitypes/vector.py

@@ -8,7 +8,7 @@
 
 from __future__ import annotations
 
-from collections.abc import Iterable, Mapping, MutableSequence
+from collections.abc import Iterable, Mapping, MutableSequence, Sequence
 from typing import TYPE_CHECKING, Any, Union, overload
 
 from typing_extensions import Self, TypeVar, final, override
@@ -79,27 +79,27 @@ def __init__(
         Returns:
             A vector data object.
         """
-        if not values:
+        backing_values = list(values)
+        if not backing_values:
             if not value_type:
                 raise TypeError("You must specify values as non-empty or specify value_type.")
             self._value_type = value_type
         else:
+            self._value_type = type(backing_values[0])
             # Validate the values input
-            for index, value in enumerate(values):
-                # Only set _value_type once.
-                if not index:
-                    self._value_type = type(value)
-
+            for value in backing_values:
                 if not isinstance(value, (bool, int, float, str)):
-                    raise invalid_arg_type("vector input data", "bool, int, float, or str", values)
+                    raise invalid_arg_type(
+                        "vector input data", "bool, int, float, or str", backing_values
+                    )
 
                 if not isinstance(value, self._value_type):
                     raise TypeError("All values in the values input must be of the same type.")
 
         if not isinstance(units, str):
             raise invalid_arg_type("units", "str", units)
 
-        self._values = list(values)
+        self._values = backing_values
         if copy_extended_properties or not isinstance(
             extended_properties, ExtendedPropertyDictionary
         ):
@@ -178,14 +178,20 @@ def __setitem__(self, index: int | slice, value: TScalar | Iterable[TScalar]) ->
                 raise TypeError("You must assign an Iterable to a Vector slice.")
             elif isinstance(value, str):  # Narrow the type to exclude string.
                 raise TypeError("You cannot assign a string to Vector slice.")
+
+            if isinstance(value, Sequence):
+                # A Sequence can be iterated over multiple times, so no need for a wrapper list.
+                replacement_values = value
             else:
-                # Assigning an empty Iterable to a slice is valid, so we don't check for empty.
-                # If an empty Iterable is assigned to a slice, that slice is deleted.
-                for subval in value:
-                    if not isinstance(subval, self._value_type):
-                        raise self._create_value_mismatch_exception(subval)
+                replacement_values = list(value)
 
-            self._values[index] = value
+            # Assigning an empty Iterable to a slice is valid, so we don't check for empty.
+            # If an empty Iterable is assigned to a slice, that slice is deleted.
+            for subval in replacement_values:
+                if not isinstance(subval, self._value_type):
+                    raise self._create_value_mismatch_exception(subval)
+
+            self._values[index] = replacement_values
 
     def __delitem__(self, index: int | slice) -> None:
         """Delete item(s) from the specified location."""

tests/unit/vector/test_vector.py

@@ -2,6 +2,7 @@
 
 import copy
 import pickle
+from collections.abc import Generator
 from typing import Any
 
 import pytest
@@ -51,22 +52,35 @@ def test___int_data_values___create___creates_with_int_data_and_default_units()
     assert data.units == ""
 
 
-def test___float_data_value___create___creates_scalar_data_with_data_and_default_units() -> None:
+def test___float_data_values___create___creates_with_float_data_and_default_units() -> None:
     data = Vector([20.2, 30.3, 40.4])
 
     assert_type(data._values[0], float)
     assert data._values == [20.2, 30.3, 40.4]
     assert data.units == ""
 
 
-def test___str_data_value___create___creates_scalar_data_with_data_and_default_units() -> None:
+def test___str_data_values___create___creates_with_str_data_and_default_units() -> None:
     data = Vector(["one", "two"])
 
     assert_type(data._values[0], str)
     assert data._values == ["one", "two"]
     assert data.units == ""
 
 
+def test___generator_data_values___create___creates_with_data_and_default_units() -> None:
+    def get_values() -> Generator[float]:
+        yield 20.2
+        yield 30.3
+        yield 40.4
+
+    data = Vector(get_values())
+
+    assert_type(data._values[0], float)
+    assert data._values == [20.2, 30.3, 40.4]
+    assert data.units == ""
+
+
 @pytest.mark.parametrize("data_value", [True, 10, 20.0, "value"])
 @pytest.mark.parametrize("units", ["volts"])
 def test___data_value_and_units___create___creates_scalar_data_with_data_and_units(
@@ -101,6 +115,29 @@ def test___invalid_data_value___create___raises_type_error(data_value: Any) -> N
     assert exc.value.args[0].startswith("The vector input data must be a bool, int, float, or str.")
 
 
+def test___invalid_generator_data_values___create___raises_type_error() -> None:
+    def get_values() -> Generator[Any]:
+        yield from [{"value_one", "value_two"}, 1.0, 2.0]
+
+    with pytest.raises(TypeError) as exc:
+        _ = Vector(get_values())
+
+    assert exc.value.args[0].startswith("The vector input data must be a bool, int, float, or str.")
+    assert "value_one" in exc.value.args[0]
+
+
+def test___empty_generator_data_values___create___raises_type_error() -> None:
+    def get_values() -> Generator[float]:
+        yield from []
+
+    with pytest.raises(TypeError) as exc:
+        _ = Vector(get_values())
+
+    assert exc.value.args[0].startswith(
+        "You must specify values as non-empty or specify value_type."
+    )
+
+
 def test___mixed_data_values___create___raises_type_error() -> None:
     with pytest.raises(TypeError) as exc:
         _ = Vector([True, "string", 1.0])
@@ -143,13 +180,27 @@ def test___vector_with_data___set_item_at_slice___values_set_correctly() -> None
     vector = Vector([1, 2, 3], "volts")
 
     vector[0:2] = [6, 7]
+
+    assert vector._values == [6, 7, 3]
+
+
+def test___vector_with_data___set_item_at_slice_with_generator___values_set_correctly() -> None:
+    def get_values() -> Generator[int]:
+        yield 6
+        yield 7
+
+    vector = Vector([1, 2, 3], "volts")
+
+    vector[0:2] = get_values()
+
     assert vector._values == [6, 7, 3]
 
 
 def test___vector_with_data___set_item_at_slice_to_empty_list___values_set_correctly() -> None:
     vector = Vector([1, 2, 3], "volts")
 
     vector[0:2] = []
+
     assert vector._values == [3]