Fix preprocess for components when type='index' (#5563)

* fix preprocess for components when type='index'

* add changeset

---------

Co-authored-by: gradio-pr-bot <gradio-pr-bot@users.noreply.github.com>

.changeset/fluffy-sloths-help.md

@@ -0,0 +1,5 @@
+---
+"gradio": minor
+---
+
+feat:Fix preprocess for components when type='index'

gradio/components/checkboxgroup.py

@@ -152,7 +152,9 @@ def update(
             "__type__": "update",
         }
 
-    def preprocess(self, x: list[str | int | float]) -> list[str | int | float]:
+    def preprocess(
+        self, x: list[str | int | float]
+    ) -> list[str | int | float] | list[int | None]:
         """
         Parameters:
             x: list of selected choices
@@ -162,7 +164,11 @@ def preprocess(self, x: list[str | int | float]) -> list[str | int | float]:
         if self.type == "value":
             return x
         elif self.type == "index":
-            return [[value for _, value in self.choices].index(choice) for choice in x]
+            choice_values = [value for _, value in self.choices]
+            return [
+                choice_values.index(choice) if choice in choice_values else None
+                for choice in x
+            ]
         else:
             raise ValueError(
                 f"Unknown type: {self.type}. Please choose from: 'value', 'index'."

gradio/components/dropdown.py

@@ -205,8 +205,8 @@ def update(
         }
 
     def preprocess(
-        self, x: str | list[str]
-    ) -> str | int | list[str] | list[int] | None:
+        self, x: str | int | float | list[str | int | float] | None
+    ) -> str | int | float | list[str | int | float] | list[int | None] | None:
         """
         Parameters:
             x: selected choice(s)
@@ -216,19 +216,17 @@ def preprocess(
         if self.type == "value":
             return x
         elif self.type == "index":
+            choice_values = [value for _, value in self.choices]
             if x is None:
                 return None
             elif self.multiselect:
+                assert isinstance(x, list)
                 return [
-                    [value for _, value in self.choices].index(choice) for choice in x
+                    choice_values.index(choice) if choice in choice_values else None
+                    for choice in x
                 ]
             else:
-                if isinstance(x, str):
-                    return (
-                        [value for _, value in self.choices].index(x)
-                        if x in self.choices
-                        else None
-                    )
+                return choice_values.index(x) if x in choice_values else None
         else:
             raise ValueError(
                 f"Unknown type: {self.type}. Please choose from: 'value', 'index'."

gradio/components/radio.py

@@ -167,7 +167,8 @@ def preprocess(self, x: str | int | float | None) -> str | int | float | None:
             if x is None:
                 return None
             else:
-                return [value for _, value in self.choices].index(x)
+                choice_values = [value for _, value in self.choices]
+                return choice_values.index(x) if x in choice_values else None
         else:
             raise ValueError(
                 f"Unknown type: {self.type}. Please choose from: 'value', 'index'."

test/test_components.py

@@ -496,7 +496,13 @@ def test_component_functions(self):
         checkboxes_input = gr.CheckboxGroup(["a", "b", "c"])
         assert checkboxes_input.preprocess(["a", "c"]) == ["a", "c"]
         assert checkboxes_input.postprocess(["a", "c"]) == ["a", "c"]
-        assert checkboxes_input.serialize(["a", "c"], True) == ["a", "c"]
+        assert checkboxes_input.serialize(["a", "c"]) == ["a", "c"]
+
+        checkboxes_input = gr.CheckboxGroup(["a", "b"], type="index")
+        assert checkboxes_input.preprocess(["a"]) == [0]
+        assert checkboxes_input.preprocess(["a", "b"]) == [0, 1]
+        assert checkboxes_input.preprocess(["a", "b", "c"]) == [0, 1, None]
+
         checkboxes_input = gr.CheckboxGroup(
             value=["a", "c"],
             choices=["a", "b", "c"],
@@ -565,6 +571,12 @@ def test_component_functions(self):
             "interactive": None,
             "root_url": None,
         }
+
+        radio = gr.Radio(choices=["a", "b"], type="index")
+        assert radio.preprocess("a") == 0
+        assert radio.preprocess("b") == 1
+        assert radio.preprocess("c") is None
+
         with pytest.raises(ValueError):
             gr.Radio(["a", "b"], type="unknown")
 
@@ -606,6 +618,16 @@ def test_component_functions(self):
         assert dropdown_input.preprocess("c full") == "c full"
         assert dropdown_input.postprocess("c full") == "c full"
 
+        dropdown = gr.Dropdown(choices=["a", "b"], type="index")
+        assert dropdown.preprocess("a") == 0
+        assert dropdown.preprocess("b") == 1
+        assert dropdown.preprocess("c") is None
+
+        dropdown = gr.Dropdown(choices=["a", "b"], type="index", multiselect=True)
+        assert dropdown.preprocess(["a"]) == [0]
+        assert dropdown.preprocess(["a", "b"]) == [0, 1]
+        assert dropdown.preprocess(["a", "b", "c"]) == [0, 1, None]
+
         dropdown_input_multiselect = gr.Dropdown(["a", "b", ("c", "c full")])
         assert dropdown_input_multiselect.preprocess(["a", "c full"]) == ["a", "c full"]
         assert dropdown_input_multiselect.postprocess(["a", "c full"]) == [