👆 💪 🌀 `dataclasses` ⏮️ 🎏 🆎 ✍ ⚒ 🐦 📊 📊.

💼, 👆 💪 ✔️ ⚙️ Pydantic ⏬ `dataclasses`. 🖼, 🚥 👆 ✔️ ❌ ⏮️ 🔁 🏗 🛠️ 🧾.

👈 💼, 👆 💪 🎯 💱 🐩 `dataclasses` ⏮️ `pydantic.dataclasses`, ❔ 💧-♻:

```{ .python .annotate hl_lines="1  5  8-11  14-17  23-25  28" }
{!../../docs_src/dataclasses/tutorial003.py!}
```

1️⃣. 👥 🗄 `field` ⚪️➡️ 🐩 `dataclasses`.

2️⃣. `pydantic.dataclasses` 💧-♻ `dataclasses`.

## 在嵌套数据结构中使用数据类

您还可以把 `dataclasses` 与其它类型注解组合在一起，创建嵌套数据结构。

还有一些情况也可以使用 Pydantic 的 `dataclasses`。例如，在 API 文档中显示错误。

本例把标准的 `dataclasses` 直接替换为 `pydantic.dataclasses`：

```{ .python .annotate hl_lines="1  5  8-11  14-17  23-25  28" }
{!../../docs_src/dataclasses/tutorial003.py!}
```

1. 本例依然要从标准的 `dataclasses` 中导入 `field`；

2. 使用 `pydantic.dataclasses` 直接替换 `dataclasses`；

 * a little different from those of other Collection-related features such as {@link
 * CollectionFeature} or {@link SetFeature}.
 *
 * <p>However, when {@link CollectionSize.Require} is used to annotate a test it behaves normally
 * (i.e. it requires the collection instance under test to be a certain size for the test to run).
 * Note that this means a test should not require more than one CollectionSize, since a particular

    }
  }
}

project.applyOsgi(
  "Export-Package: okhttp3,okhttp3.internal.*;okhttpinternal=true;mandatory:=okhttpinternal",
  "Import-Package: " +
    "android.*;resolution:=optional," +
    "com.oracle.svm.core.annotate;resolution:=optional," +
    "com.oracle.svm.core.configure;resolution:=optional," +
    "dalvik.system;resolution:=optional," +
    "org.conscrypt;resolution:=optional," +
    "org.bouncycastle.*;resolution:=optional," +

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

### 📁

🔜 🎏 🏗 📁 ✍ 📁 `Dockerfile` ⏮️:

```{ .dockerfile .annotate }
# (1)
FROM python:3.9

# (2)
WORKDIR /code

# (3)
COPY ./requirements.txt /code/requirements.txt

# (4)
RUN pip install --no-cache-dir --upgrade -r /code/requirements.txt

# (5)

In diesem Fall können Sie einfach die Standard-`dataclasses` durch `pydantic.dataclasses` ersetzen, was einen direkten Ersatz darstellt:

```{ .python .annotate hl_lines="1  5  8-11  14-17  23-25  28" }
{!../../docs_src/dataclasses/tutorial003.py!}
```

1. Wir importieren `field` weiterhin von Standard-`dataclasses`.

   * could use null, but that messes with our nullness checking, including under J2KT. We could
   * probably work around it by changing how we annotate the J2CL EnumMap, but that's probably more
   * trouble than just using Object.class.)
   *
   * Then we declare the getters for these fields as @GwtIncompatible so that no one can try to use

   * could use null, but that messes with our nullness checking, including under J2KT. We could
   * probably work around it by changing how we annotate the J2CL EnumMap, but that's probably more
   * trouble than just using Object.class.)
   *
   * Then we declare the getters for these fields as @GwtIncompatible so that no one can try to use

👈 🌌, 👆 🚫 ✔️ ✍ ⚫️ 🌐 🥇 💾, & 👆 💪 🚶‍♀️ 👈 🚂 🔢 `StreamingResponse`, & 📨 ⚫️.

👉 🔌 📚 🗃 🔗 ⏮️ ☁ 💾, 📹 🏭, & 🎏.

```{ .python .annotate hl_lines="2  10-12  14" }
{!../../docs_src/custom_response/tutorial008.py!}
```

1️⃣. 👉 🚂 🔢. ⚫️ "🚂 🔢" ↩️ ⚫️ 🔌 `yield` 📄 🔘.
2️⃣. ⚙️ `with` 🍫, 👥 ⚒ 💭 👈 📁-💖 🎚 📪 ⏮️ 🚂 🔢 🔨. , ⏮️ ⚫️ 🏁 📨 📨.

    scheme: slate
    primary: teal
    accent: amber
    toggle:
      icon: material/lightbulb-outline
      name: Switch to system preference
  features:
  - content.code.annotate
  - content.code.copy
  # - content.code.select
  - content.footnote.tooltips
  - content.tabs.link
  - content.tooltips
  - navigation.footer
  - navigation.indexes
  - navigation.instant