Function to check if all elements are of the same type (#1)

Add tests, include example in README

README.md

@@ -68,3 +68,16 @@ y = np.array([10, 20, 30, 40, 50])
 biocutils.subset(y, [0, 2, 4])
 ## array([10, 30, 50])
 ```
+
+### `is_list_of_type`
+
+Checks if all elements of a list or tuple are of the same type.
+
+```python
+import biocutils
+import numpy as np
+
+x = [np.random.rand(3), np.random.rand(3, 2)]
+biocutils.is_list_of_type(x, np.ndarray)
+## True
+```

src/biocutils/__init__.py

@@ -21,3 +21,4 @@
 from .intersect import intersect
 from .union import union
 from .subset import subset
+from .is_list_of_type import is_list_of_type

src/biocutils/is_list_of_type.py

@@ -0,0 +1,21 @@
+from typing import Any
+
+__author__ = "jkanche"
+__copyright__ = "jkanche"
+__license__ = "MIT"
+
+
+def is_list_of_type(x: Any, target_type) -> bool:
+    """Checks if ``x`` is a list, and whether all elements of the list are of the same type.
+
+    Args:
+        x (Any): Any list-like object.
+        target_type (callable): Type to check for, e.g. ``str``, ``int``.
+
+    Returns:
+        bool: True if ``x`` is :py:class:`list` or :py:class:`tuple` and
+        all elements are of the same type.
+    """
+    return isinstance(x, (list, tuple)) and all(
+        isinstance(item, target_type) for item in x
+    )

tests/test_utils.py

@@ -0,0 +1,27 @@
+import numpy as np
+import pytest
+from biocutils import is_list_of_type
+
+
+def test_simple_list():
+    x = [1, 2, 3]
+
+    assert is_list_of_type(x, int)
+
+    y = [1.2, 2.3, 4.5]
+    assert is_list_of_type(y, float)
+
+    xt = (1, 2, 3)
+    assert is_list_of_type(xt, int)
+
+
+def test_should_fail():
+    x = [1, [2, 3, 4], 6]
+
+    assert is_list_of_type(x, int) is False
+
+
+def test_numpy_elems():
+    x = [np.random.rand(3), np.random.rand(3, 2)]
+
+    assert is_list_of_type(x, np.ndarray)