✨ Allow deletion of fields on entries by key (#445)

bibtexparser/model.py

@@ -304,6 +304,16 @@ def set_field(self, field: Field):
         else:
             self._fields.append(field)
 
+    def pop_field(self, key: str) -> Optional[Field]:
+        """Removes and returns the field with the given key, if present."""
+        try:
+            field = self.fields_dict.pop(key)
+        except KeyError:
+            return None
+
+        self._fields = [f for f in self._fields if f.key != key]
+        return field
+
     def __getitem__(self, key: str) -> Any:
         """Dict-mimicking index.
 
@@ -326,6 +336,14 @@ def __setitem__(self, key: str, value: Any):
         """
         self.set_field(Field(key, value))
 
+    def __delitem__(self, key):
+        """Dict-mimicking index.
+
+        This serves for partial v1.x backwards compatibility,
+        as well as for a shorthand for `pop_field`.
+        """
+        self.pop_field(key)
+
     def items(self):
         """Dict-mimicking, for partial v1.x backwards compatibility.
 

tests/test_model.py

@@ -1,6 +1,8 @@
 from copy import copy, deepcopy
 from textwrap import dedent
 
+import pytest
+
 from bibtexparser.model import (
     Entry,
     ExplicitComment,
@@ -311,3 +313,9 @@ def test_entry_fields_shorthand():
     assert entry.fields_dict["myNewField"].key == "myNewField"
     assert entry.fields_dict["myNewField"].value == "new_value"
     assert entry.fields_dict["myNewField"].start_line is None
+
+    del entry["myNewField"]
+    assert "myNewField" not in entry.fields_dict
+    assert len([f for f in entry.fields if f.key == "myNewField"]) == 0
+    with pytest.raises(KeyError):
+        entry["myNewField"]