deprecated=True,
        ),
    ] = None,
):
    results = {"items": [{"item_id": "Foo"}, {"item_id": "Bar"}]}
    if q:
        results.update({"q": q})

    ),
):
    results = {"items": [{"item_id": "Foo"}, {"item_id": "Bar"}]}
    if q:
        results.update({"q": q})

但是你仍然需要使用 `Path` 来声明路径参数 `item_id`。

如果你将带有「默认值」的参数放在没有「默认值」的参数之前，Python 将会报错。

但是你可以对其重新排序，并将不带默认值的值（查询参数 `q`）放到最前面。

对 **FastAPI** 来说这无关紧要。它将通过参数的名称、类型和默认值声明（`Query`、`Path` 等）来检测参数，而不在乎参数的顺序。

因此，你可以将函数声明为：

{* ../../docs_src/path_params_numeric_validations/tutorial002.py hl[7] *}

## 按需对参数排序的技巧

如果你想不使用 `Query` 声明没有默认值的查询参数 `q`，同时使用 `Path` 声明路径参数 `item_id`，并使它们的顺序与上面不同，Python 对此有一些特殊的语法。

        "openapi": "3.1.0",
        "info": {"title": "FastAPI", "version": "0.1.0"},
        "paths": {
            "/items/{item_id}": {
                "get": {
                    "responses": {
                        "404": {"description": "Item not found"},
                        "302": {"description": "The item was moved"},
                        "403": {"description": "Not enough privileges"},
                        "200": {

        "paths": {
            "/items/{item_id}": {
                "put": {
                    "summary": "Update Item",
                    "operationId": "update_item_items__item_id__put",
                    "parameters": [
                        {
                            "required": True,
                            "schema": {"title": "Item Id", "type": "integer"},

from docs_src.custom_response.tutorial001b_py39 import app

client = TestClient(app)


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


def test_openapi_schema():
    response = client.get("/openapi.json")
    assert response.status_code == 200, response.text
    assert response.json() == {

        "paths": {
            "/items/{item_id}": {
                "put": {
                    "parameters": [
                        {
                            "in": "path",
                            "name": "item_id",
                            "required": True,
                            "schema": {
                                "title": "Item Id",
                                "type": "integer",

from fastapi import FastAPI
from fastapi.responses import ORJSONResponse

app = FastAPI(default_response_class=ORJSONResponse)


@app.get("/items/")
async def read_items():

from fastapi import FastAPI

app = FastAPI()


@app.get("/items/", openapi_extra={"x-aperture-labs-portal": "blue"})
async def read_items():

    response = client.put(
        "/items/5",
        json={
            "importance": 2,
            "item": {"name": "Foo", "price": 50.5},
            "user": {"username": "Dave"},
        },
        params={"q": "somequery"},
    )
    assert response.status_code == 200
    assert response.json() == {
        "item_id": 5,
        "importance": 2,
        "item": {
            "name": "Foo",