2948 Enhance the transform to delete items

monai/transforms/utility/dictionary.py

@@ -17,6 +17,7 @@
 
 import copy
 import logging
+import re
 from copy import deepcopy
 from typing import Any, Callable, Dict, Hashable, List, Mapping, Optional, Sequence, Tuple, Union
 
@@ -637,8 +638,38 @@ class DeleteItemsd(MapTransform):
     It will remove the key-values and copy the others to construct a new dictionary.
     """
 
+    def __init__(
+        self,
+        keys: KeysCollection,
+        sep: str = ".",
+        use_re: Union[Sequence[bool], bool] = False,
+    ) -> None:
+        """
+        Args:
+            keys: keys of the corresponding items to delete, can be "A{sep}B{sep}C"
+                to delete key `C` in nested dictionary, `C` can be regular expression.
+                See also: :py:class:`monai.transforms.compose.MapTransform`
+            sep: the separator tag to define nested dictionary keys, default to ".".
+            use_re: whether the specified key is a regular expression, it also can be
+                a list of bool values, map the to keys.
+        """
+        super().__init__(keys)
+        self.sep = sep
+        self.use_re = ensure_tuple_rep(use_re, len(self.keys))
+
     def __call__(self, data):
-        return {key: val for key, val in data.items() if key not in self.key_iterator(data)}
+        def _delete_item(keys, d, use_re: bool = False):
+            key = keys[0]
+            if len(keys) > 1:
+                d[key] = _delete_item(keys[1:], d[key], use_re)
+                return d
+            return {k: v for k, v in d.items() if (use_re and not re.search(key, k)) or (not use_re and k != key)}
+
+        d = dict(data)
+        for key, use_re in zip(self.keys, self.use_re):
+            d = _delete_item(key.split(self.sep), d, use_re)
+
+        return d
 
 
 class SelectItemsd(MapTransform):

tests/test_delete_itemsd.py

@@ -19,19 +19,36 @@
 
 TEST_CASE_1 = [{"keys": [str(i) for i in range(30)]}, 20]
 
+TEST_CASE_2 = [{"keys": ["image/" + str(i) for i in range(30)], "sep": "/"}, 20]
+
+TEST_CASE_3 = [{"keys": "meta_dict%0008\\|[0-9]", "sep": "%", "use_re": True}]
+
 
 class TestDeleteItemsd(unittest.TestCase):
-    @parameterized.expand([TEST_CASE_1])
+    @parameterized.expand([TEST_CASE_1, TEST_CASE_2])
     def test_memory(self, input_param, expected_key_size):
-        input_data = {}
+        input_data = {"image": {}} if "sep" in input_param else {}
         for i in range(50):
-            input_data[str(i)] = [time.time()] * 100000
+            if "sep" in input_param:
+                input_data["image"][str(i)] = [time.time()] * 100000
+            else:
+                input_data[str(i)] = [time.time()] * 100000
         result = DeleteItemsd(**input_param)(input_data)
-        self.assertEqual(len(result.keys()), expected_key_size)
+        if "sep" in input_param:
+            self.assertEqual(len(result["image"].keys()), expected_key_size)
+        else:
+            self.assertEqual(len(result.keys()), expected_key_size)
         self.assertGreaterEqual(
             sys.getsizeof(input_data) * float(expected_key_size) / len(input_data), sys.getsizeof(result)
         )
 
+    @parameterized.expand([TEST_CASE_3])
+    def test_re(self, input_param):
+        input_data = {"image": [1, 2, 3], "meta_dict": {"0008|0005": 1, "0008|1050": 2, "0008test": 3}}
+        result = DeleteItemsd(**input_param)(input_data)
+        self.assertEqual(result["meta_dict"]["0008test"], 3)
+        self.assertTrue(len(result["meta_dict"]), 1)
+
 
 if __name__ == "__main__":
     unittest.main()