!!! info
    你还可以使用：

    * `response_model_exclude_defaults=True`
    * `response_model_exclude_none=True`

    参考 <a href="https://docs.pydantic.dev/latest/concepts/serialization/#modeldict" class="external-link" target="_blank">Pydantic 文档</a> 中对 `exclude_defaults` 和 `exclude_none` 的描述。

#### 默认值字段有实际值的数据

    assert jsonable_encoder(model, exclude_unset=True) == {"foo": "foo", "bar": "bar"}
    assert jsonable_encoder(model, exclude_defaults=True) == {"foo": "foo"}
    assert jsonable_encoder(model, exclude_unset=True, exclude_defaults=True) == {
        "foo": "foo"
    }
    assert jsonable_encoder(model, include={"foo"}) == {"foo": "foo"}
    assert jsonable_encoder(model, exclude={"bla"}) == {"foo": "foo", "bar": "bar"}

!!! info "情報"
    以下も使用することができます:

    * `response_model_exclude_defaults=True`
    * `response_model_exclude_none=True`

  <build>
    <plugins>
      <plugin>
        <artifactId>maven-surefire-plugin</artifactId>
        <configuration>
          <excludes>
            <exclude>org/codehaus/plexus/util/FileBasedTestCase.java</exclude>
            <exclude>**/Test*.java</exclude>
          </excludes>
        </configuration>
      </plugin>
    </plugins>
  </build>
  <distributionManagement>
    <status>deployed</status>

issues:
  # Which dirs to exclude: issues from them won't be reported.
  # Can use regexp here: `generated.*`, regexp is applied on full path,
  # including the path prefix if one is set.
  # Default dirs are skipped independently of this option's value (see exclude-dirs-use-default).
  # "/" will be replaced by current OS file path separator to properly work on Windows.
  # Default: []
  exclude-dirs:
    - genfiles$
    - vendor$

    implementation(project(":binary-compatibility"))

    implementation("org.codenarc:CodeNarc") {
        exclude(group = "org.apache.groovy")
        exclude(group = "org.codehaus.groovy")
    }
    implementation("com.github.javaparser:javaparser-symbol-solver-core") {
        exclude(group = "com.google.guava")
    }
    implementation("org.gradle.kotlin:gradle-kotlin-dsl-conventions")

        additional-arguments: --no-configuration-cache
      env:
        # Exclude some projects and configurations that should not contribute to the dependency graph
        DEPENDENCY_GRAPH_EXCLUDE_PROJECTS: ':docs|:internal-performance-testing|:enterprise-plugin-performance|:performance|:internal-integ-testing'

    /**
     *
     */
    public String xyz_value = "xyz";

    /**
     *
     */
    public String other = "other";

    /**
     *
     */
    public String abc_exclude = "exclude";

    /**
     *
     */
    public String ab = "ab";

    `PATCH` 没有 `PUT` 知名，也怎么不常用。

    很多人甚至只用 `PUT` 实现部分更新。

    **FastAPI** 对此没有任何限制，可以**随意**互换使用这两种操作。

    但本指南也会分别介绍这两种操作各自的用途。

### 使用 Pydantic 的 `exclude_unset` 参数

更新部分数据时，可以在 Pydantic 模型的 `.dict()` 中使用 `exclude_unset` 参数。

比如，`item.dict(exclude_unset=True)`。

这段代码生成的 `dict` 只包含创建 `item` 模型时显式设置的数据，而不包括默认值。

然后再用它生成一个只含已设置（在请求中所发送）数据，且省略了默认值的 `dict`：

```Python hl_lines="34"

!!! info "정보"
    아래 또한 사용할 수 있습니다:

    * `response_model_exclude_defaults=True`
    * `response_model_exclude_none=True`

    <a href="https://docs.pydantic.dev/latest/concepts/serialization/#modeldict" class="external-link" target="_blank">Pydantic 문서</a>에서 `exclude_defaults` 및 `exclude_none`에 대해 설명한 대로 사용할 수 있습니다.

#### 기본값이 있는 필드를 갖는 값의 데이터