feat: add find helper methods

Author: cuinixam

src/py_app_dev/core/find.py

@@ -0,0 +1,23 @@
+"""Utility functions for working with collections and type filtering."""
+
+from typing import Any, Callable, Optional, TypeVar
+
+T = TypeVar("T")
+
+
+def find_elements_of_type(elements: list[Any], element_type: type[T]) -> list[T]:
+    """Find all elements of a specific type."""
+    return [elem for elem in elements if isinstance(elem, element_type)]
+
+
+def filter_elements(elements: list[T], filter_fn: Callable[[T], bool]) -> list[T]:
+    """Filter elements based on a predicate function."""
+    return [elem for elem in elements if filter_fn(elem)]
+
+
+def find_first_element_of_type(elements: list[Any], element_type: type[T], filter_fn: Optional[Callable[[T], bool]] = None) -> Optional[T]:
+    """Find the first element of a specific type, optionally matching a filter condition."""
+    filtered_elements = find_elements_of_type(elements, element_type)
+    if filter_fn:
+        filtered_elements = filter_elements(filtered_elements, filter_fn)
+    return filtered_elements[0] if filtered_elements else None

tests/test_find.py

@@ -0,0 +1,39 @@
+from dataclasses import dataclass
+
+from py_app_dev.core.find import filter_elements, find_elements_of_type, find_first_element_of_type
+
+
+@dataclass
+class Person:
+    name: str
+    age: int
+
+
+def test_find_elements_of_type():
+    elements = [1, "hello", 2, "world", 3.14]
+
+    strings = find_elements_of_type(elements, str)
+    assert strings == ["hello", "world"]
+
+    integers = find_elements_of_type(elements, int)
+    assert integers == [1, 2]
+
+
+def test_filter_elements():
+    numbers = [1, 2, 3, 4, 5]
+    evens = filter_elements(numbers, lambda x: x % 2 == 0)
+    assert evens == [2, 4]
+
+
+def test_find_first_element_of_type():
+    people = [Person("Alice", 30), Person("Bob", 25)]
+    elements = [1, "hello", people[0], 2, people[1]]
+
+    first_person = find_first_element_of_type(elements, Person)
+    assert first_person == people[0]
+
+    young_person = find_first_element_of_type(elements, Person, lambda p: p.age < 30)
+    assert young_person == people[1]
+
+    old_person = find_first_element_of_type(elements, Person, lambda p: p.age > 50)
+    assert old_person is None