Add get_param_names helper function.

src/pywrangler/util/helper.py

@@ -2,7 +2,10 @@
 
 """
 
-from typing import Callable
+import inspect
+from typing import Callable, List
+
+from pywrangler.util.types import T_STR_OPT_MUL
 
 
 def cached_property(method: Callable) -> property:
@@ -36,3 +39,32 @@ def get_prop_value(obj):
             return value
 
     return property(get_prop_value, doc=docstring)
+
+
+def get_param_names(func: Callable,
+                    ignore: T_STR_OPT_MUL = None) -> List[str]:
+    """Retrieve all parameter names for given function.
+
+    Parameters
+    ----------
+    func: Callable
+        Function for which parameter names should be retrieved.
+    ignore: iterable, None, optional
+        Parameter names to be ignored. For example, `self` for `__init__`
+        functions.
+
+    Returns
+    -------
+    param_names: list
+        List of parameter names.
+
+    """
+
+    ignore = ignore or []
+
+    signature = inspect.signature(func)
+    parameters = signature.parameters.values()
+
+    param_names = [x.name for x in parameters if x.name not in ignore]
+
+    return param_names

src/pywrangler/util/types.py

@@ -4,5 +4,8 @@
 
 from typing import Iterable, Union
 
-TYPE_COLUMNS = Union[str, Iterable[str], None]
+T_STR_OPT_MUL = Union[Iterable[str], None]
+T_STR_OPT_SING_MUL = Union[str, Iterable[str], None]
+
+TYPE_COLUMNS = T_STR_OPT_SING_MUL
 TYPE_ASCENDING = Union[bool, Iterable[bool], None]

tests/util/test_helper.py

@@ -0,0 +1,19 @@
+"""This module contains tests for the helper module.
+
+"""
+
+from pywrangler.util.helper import get_param_names
+
+
+def test_get_param_names():
+
+    def func():
+        pass
+
+    assert get_param_names(func) == []
+
+    def func1(a, b=4, c=6):
+        pass
+
+    assert get_param_names(func1) == ["a", "b", "c"]
+    assert get_param_names(func1, ["a"]) == ["b", "c"]