from typing import Union

from fastapi import FastAPI

app = FastAPI()


@app.get("/items/{item_id}")
async def read_item(item_id: str, q: Union[str, None] = None):
    if q:
        return {"item_id": item_id, "q": q}

由于列表是带有"子类型"的类型，所以我们把子类型放在方括号中：

{* ../../docs_src/python_types/tutorial006.py hl[4] *}


这表示："变量 `items` 是一个 `list`，并且这个列表里的每一个元素都是 `str`"。

这样，即使在处理列表中的元素时，你的编辑器也可以提供支持。

没有类型，几乎是不可能实现下面这样：

<img src="https://fastapi.tiangolo.com/img/python-types/image05.png">

注意，变量 `item` 是列表 `items` 中的元素之一。

而且，编辑器仍然知道它是一个 `str`，并为此提供了支持。

#### 元组和集合

声明 `tuple` 和 `set` 的方法也是一样的：

constraints.URL.message = {item} is geen geldige URL.
constraints.Required.message = {item} is vereist.
constraints.TypeInteger.message = {item} moet een getal zijn.
constraints.TypeLong.message = {item} moet een getal zijn.
constraints.TypeFloat.message = {item} moet een getal zijn.
constraints.TypeDouble.message = {item} moet een getal zijn.
constraints.TypeAny.message = {item} kan niet worden geconverteerd naar {propertyType}.

constraints.URL.message = {item} - неверный URL-адрес.
constraints.Required.message = {item} обязательно.
constraints.TypeInteger.message = {item} должно быть числом.
constraints.TypeLong.message = {item} должно быть числом.
constraints.TypeFloat.message = {item} должно быть числом.
constraints.TypeDouble.message = {item} должно быть числом.
constraints.TypeAny.message = {item} не может быть преобразовано в {propertyType}.

from pydantic import BaseModel

app = FastAPI()


class Cookies(BaseModel):
    session_id: str
    fatebook_tracker: str | None = None
    googall_tracker: str | None = None


@app.get("/items/")
async def read_items(cookies: Cookies = Cookie()):

from typing import Annotated, Union

from fastapi import FastAPI, Query

app = FastAPI()


@app.get("/items/")
async def read_items(
    hidden_query: Annotated[Union[str, None], Query(include_in_schema=False)] = None,
):
    if hidden_query:
        return {"hidden_query": hidden_query}
    else:

    // Each group is a List of items, each item has a list of factory args.
    List<List<List<Object>>> argGroups = new ArrayList<>();
    argGroups.add(ImmutableList.of(args, equalArgs));
    EqualsTester tester =
        new EqualsTester(
            /* itemReporter= */ item -> {
              List<Object> factoryArgs = argGroups.get(item.groupNumber).get(item.itemNumber);
              return factory.getName()

import org.opensearch.transport.client.Client;

/**
 * SuggestBulkFileWriter is an implementation of the SuggestWriter interface.
 * This class is responsible for writing and deleting suggest items in bulk.
 *
 * <p>Currently, the methods in this class throw UnsupportedOperationException
 * as they are not yet implemented.</p>
 *
 * @see SuggestWriter
 */

        "custom_field": [1.0, 2.0, 3.0]
    }
    assert ta.json_schema() == snapshot(
        {
            "properties": {
                "custom_field": {
                    "items": {"type": "number"},
                    "title": "Custom Field",
                    "type": "array",
                }
            },
            "required": ["custom_field"],
            "title": "MyModel",

constraints.URL.message = {item} non è un URL valido.
constraints.Required.message = {item} è richiesto.
constraints.TypeInteger.message = {item} deve essere un numero.
constraints.TypeLong.message = {item} deve essere un numero.
constraints.TypeFloat.message = {item} deve essere un numero.
constraints.TypeDouble.message = {item} deve essere un numero.
constraints.TypeAny.message = {item} non può essere convertito in {propertyType}.