feat: inclusive_subdict, exclusive_subdict

lkj/__init__.py

@@ -8,7 +8,7 @@
     get_by_value,  # Get a dictionary from a list of dictionaries by a field value
 )
 from lkj.funcs import mk_factory
-from lkj.dicts import truncate_dict_values
+from lkj.dicts import truncate_dict_values, inclusive_subdict, exclusive_subdict
 from lkj.filesys import get_app_data_dir, get_watermarked_dir, enable_sourcing_from_file
 from lkj.strings import (
     regex_based_substitution,

lkj/dicts.py

@@ -9,6 +9,38 @@
 from typing import Optional
 
 
+def inclusive_subdict(d, include):
+    """
+    Returns a new dictionary with only the keys in `include`.
+
+    Parameters:
+    d (dict): The input dictionary.
+    include (set): The set of keys to include in the new dictionary.
+
+    Example:
+    >>> inclusive_subdict({'a': 1, 'b': 2, 'c': 3}, {'a', 'c'})
+    {'a': 1, 'c': 3}
+
+    """
+    return {k: d[k] for k in d.keys() & include}
+
+
+def exclusive_subdict(d, exclude):
+    """
+    Returns a new dictionary with only the keys not in `exclude`.
+
+    Parameters:
+    d (dict): The input dictionary.
+    exclude (set): The set of keys to exclude from the new dictionary.
+
+    Example:
+    >>> exclusive_subdict({'a': 1, 'b': 2, 'c': 3}, {'a', 'c'})
+    {'b': 2}
+    
+    """
+    return {k: d[k] for k in d.keys() - exclude}
+
+
 # Note: There is a copy of truncate_dict_values in the ju package.
 def truncate_dict_values(
     d: dict,