=== "Python 3.10+"

    ```Python hl_lines="3"
    {!> ../../../docs_src/cookie_params/tutorial001_an_py310.py!}
    ```

=== "Python 3.9+"

    ```Python hl_lines="3"
    {!> ../../../docs_src/cookie_params/tutorial001_an_py39.py!}
    ```

=== "Python 3.8+"

    ```Python hl_lines="3"
    {!> ../../../docs_src/cookie_params/tutorial001_an.py!}
    ```

=== "Python 3.10+ non-Annotated"

    !!! tip

```Python hl_lines="6  11"
{!../../../docs_src/path_params/tutorial003.py!}
```

Otherwise, the path for `/users/{user_id}` would match also for `/users/me`, "thinking" that it's receiving a parameter `user_id` with a value of `"me"`.

Similarly, you cannot redefine a path operation:

```Python hl_lines="6  11"
{!../../../docs_src/path_params/tutorial003b.py!}
```

```Python hl_lines="16"
{!../../../docs_src/path_params/tutorial005.py!}
```

### 查看文档

 API 文档会显示预定义*路径参数*的可用值：

<img src="/img/tutorial/path-params/image03.png">

### 使用 Python _枚举类型_

*路径参数*的值是枚举的元素。

#### 比较*枚举元素*

枚举类 `ModelName` 中的*枚举元素*支持比较操作：

```Python hl_lines="17"
{!../../../docs_src/path_params/tutorial005.py!}
```

#### 获取*枚举值*

## 🗄 ➡

🥇, 🗄 `Path` ⚪️➡️ `fastapi`:

=== "🐍 3️⃣.6️⃣ & 🔛"

    ```Python hl_lines="3"
    {!> ../../../docs_src/path_params_numeric_validations/tutorial001.py!}
    ```

=== "🐍 3️⃣.1️⃣0️⃣ & 🔛"

    ```Python hl_lines="1"
    {!> ../../../docs_src/path_params_numeric_validations/tutorial001_py310.py!}
    ```

## 📣 🗃

👆 💪 📣 🌐 🎏 🔢 `Query`.

🖼, 📣 `title` 🗃 💲 ➡ 🔢 `item_id` 👆 💪 🆎:

    )

    test_override_in_items_with_q()


@needs_py310
def test_override_in_items_with_params_run():
    from docs_src.dependency_testing.tutorial001_py310 import (
        test_override_in_items_with_params,
    )

    test_override_in_items_with_params()


@needs_py310
def test_override_in_users():
    from docs_src.dependency_testing.tutorial001_py310 import client

        "message": "Hello Items!",
        "params": {"q": None, "skip": 5, "limit": 10},
    }


def test_override_in_items_with_q():
    response = client.get("/items/?q=foo")
    assert response.status_code == 200
    assert response.json() == {
        "message": "Hello Items!",
        "params": {"q": "foo", "skip": 5, "limit": 10},
    }


def test_override_in_items_with_params():

def get_client():
    from docs_src.query_params_str_validations.tutorial010_an import app

    client = TestClient(app)
    return client


def test_query_params_str_validations_no_query(client: TestClient):
    response = client.get("/items/")
    assert response.status_code == 200
    assert response.json() == {"items": [{"item_id": "Foo"}, {"item_id": "Bar"}]}

import pytest
from dirty_equals import IsDict
from fastapi.testclient import TestClient

from ...utils import needs_py310


@pytest.fixture(name="client")
def get_client():
    from docs_src.header_params.tutorial002_py310 import app

    client = TestClient(app)
    return client


@needs_py310
@pytest.mark.parametrize(
    "path,headers,expected_status,expected_response",
    [

    ```Python hl_lines="11-14"
    {!> ../../../docs_src/body_fields/tutorial001.py!}
    ```

`Field` 的工作方式和 `Query`、`Path`、`Body` 相同，参数也相同。

!!! note "技术细节"

    实际上，`Query`、`Path` 都是 `Params` 的子类，而 `Params` 类又是 Pydantic 中 `FieldInfo` 的子类。

    Pydantic 的 `Field` 返回也是 `FieldInfo` 的类实例。

    `Body` 直接返回的也是 `FieldInfo` 的子类的对象。后文还会介绍一些 `Body` 的子类。

    注意，从 `fastapi` 导入的 `Query`、`Path` 等对象实际上都是返回特殊类的函数。

    [
        ("/items/", 200, [{"name": "Foo", "price": 42}]),
        ("/users/", 200, [{"username": "johndoe"}]),
        ("/elements/", 200, [{"item_id": "Foo"}]),
    ],
)
def test_query_params_str_validations(path, expected_status, expected_response):
    response = client.get(path)
    assert response.status_code == expected_status
    assert response.json() == expected_response


def test_openapi_schema():