## 🗄 `Field`

🥇, 👆 ✔️ 🗄 ⚫️:

=== "🐍 3️⃣.6️⃣ & 🔛"

    ```Python hl_lines="4"
    {!> ../../../docs_src/body_fields/tutorial001.py!}
    ```

=== "🐍 3️⃣.1️⃣0️⃣ & 🔛"

    ```Python hl_lines="2"
    {!> ../../../docs_src/body_fields/tutorial001_py310.py!}
    ```

!!! warning

## Імпорт `Field`

Спочатку вам потрібно імпортувати це:

=== "Python 3.10+"

    ```Python hl_lines="4"
    {!> ../../../docs_src/body_fields/tutorial001_an_py310.py!}
    ```

=== "Python 3.9+"

    ```Python hl_lines="4"
    {!> ../../../docs_src/body_fields/tutorial001_an_py39.py!}
    ```

=== "Python 3.8+"

                    "type": "missing",
                    "loc": ["body", "file"],
                    "msg": "Field required",
                    "input": None,
                },
                {
                    "type": "missing",
                    "loc": ["body", "fileb"],
                    "msg": "Field required",
                    "input": None,
                },
                {

from fastapi import FastAPI
from pydantic import BaseModel, Field

app = FastAPI()


class Item(BaseModel):
    name: str = Field(examples=["Foo"])
    description: str | None = Field(default=None, examples=["A very nice Item"])
    price: float = Field(examples=[35.4])
    tax: float | None = Field(default=None, examples=[3.2])


@app.put("/items/{item_id}")
async def update_item(item_id: int, item: Item):

                    "type": "missing",
                    "loc": ["body", "item"],
                    "msg": "Field required",
                    "input": None,
                },
                {
                    "type": "missing",
                    "loc": ["body", "user"],
                    "msg": "Field required",
                    "input": None,
                },
                {

## Importe `Field`

Primeiro, você tem que importá-lo:

```Python hl_lines="4"
{!../../../docs_src/body_fields/tutorial001.py!}
```

!!! warning "Aviso"
    Note que `Field` é importado diretamente do `pydantic`, não do `fastapi` como todo o resto (`Query`, `Path`, `Body`, etc).

# Body - Fields

The same way you can declare additional validation and metadata in *path operation function* parameters with `Query`, `Path` and `Body`, you can declare validation and metadata inside of Pydantic models using Pydantic's `Field`.

## Import `Field`

First, you have to import it:

=== "Python 3.10+"

    ```Python hl_lines="4"
    {!> ../../../docs_src/body_fields/tutorial001_an_py310.py!}
    ```

=== "Python 3.9+"

与在*路径操作函数*中使用 `Query`、`Path` 、`Body` 声明校验与元数据的方式一样，可以使用 Pydantic 的 `Field` 在 Pydantic 模型内部声明校验和元数据。

## 导入 `Field`

首先，从 Pydantic 中导入 `Field`：

=== "Python 3.10+"

    ```Python hl_lines="4"
    {!> ../../../docs_src/body_fields/tutorial001_an_py310.py!}
    ```

=== "Python 3.9+"

    ```Python hl_lines="4"
    {!> ../../../docs_src/body_fields/tutorial001_an_py39.py!}
    ```

=== "Python 3.8+"

    # Core Vocabulary
    schema_: Optional[str] = Field(default=None, alias="$schema")
    vocabulary: Optional[str] = Field(default=None, alias="$vocabulary")
    id: Optional[str] = Field(default=None, alias="$id")
    anchor: Optional[str] = Field(default=None, alias="$anchor")
    dynamicAnchor: Optional[str] = Field(default=None, alias="$dynamicAnchor")
    ref: Optional[str] = Field(default=None, alias="$ref")

from fastapi import Body, FastAPI
from pydantic import BaseModel, Field

app = FastAPI()


class Item(BaseModel):
    name: str
    description: str | None = Field(
        default=None, title="The description of the item", max_length=300
    )
    price: float = Field(gt=0, description="The price must be greater than zero")
    tax: float | None = None


@app.put("/items/{item_id}")