Aynı hata <a href="http://127.0.0.1:8000/items/4.2" class="external-link" target="_blank">http://127.0.0.1:8000/items/4.2</a> sayfasında olduğu gibi `int` yerine `float` bir değer verseydik de ortaya çıkardı.

/// check | Ek bilgi

Böylece, aynı Python tip tanımlaması ile birlikte, **FastAPI** veri doğrulama özelliği sağlar.

      "input": "foo"
    }
  ]
}
```
тому що параметр шляху має значення `"foo"`, яке не є типом `int`.

Таку саму помилку отримаємо, якщо передати `float` замість `int`, як бачимо, у цьому прикладі: <a href="http://127.0.0.1:8000/items/4.2" class="external-link" target="_blank">http://127.0.0.1:8000/items/4.2</a>

/// check | Примітка

					<div class="row mb-2">
						<div class="col-sm-6">
							<h1>
								<la:message key="labels.storage_configuration" />
							</h1>
						</div>
						<div class="col-sm-6">
							<ol class="breadcrumb float-sm-right">
								<li class="breadcrumb-item"><la:link href="/admin/storage/">
										<la:message key="labels.crud_link_list" />
									</la:link></li>

                            <la:message key="labels.dict_stopwords_title"/>
                        </h1>
                    </div>
                    <div class="col-sm-6">
                        <ol class="breadcrumb float-sm-right">
                            <li class="breadcrumb-item"><la:link href="/admin/dict">
                                <la:message key="labels.dict_list_link"/>
                            </la:link></li>

          new TestHasher().putUnencodedChars(s).hash(),
          new TestHasher().putString(s, UTF_16LE).hash());
    }
  }

  public void testFloat() {
    TestHasher hasher = new TestHasher();
    hasher.putFloat(Float.intBitsToFloat(0x04030201));
    hasher.assertBytes(new byte[] {1, 2, 3, 4});
  }

  public void testDouble() {
    TestHasher hasher = new TestHasher();
    hasher.putDouble(Double.longBitsToDouble(0x0807060504030201L));

		{"DATA", "·A(SB)/4,0", "DATA value must be an immediate constant or address"},
		{"DATA", "·B(SB)/4,$0", ""},
		{"DATA", "·C(SB)/5,$0", "bad int size for DATA argument: 5"},
		{"DATA", "·D(SB)/5,$0.0", "bad float size for DATA argument: 5"},
		{"DATA", "·E(SB)/4,$·A(SB)", "bad addr size for DATA argument: 4"},
		{"DATA", "·F(SB)/8,$·A(SB)", ""},
		{"DATA", "·G(SB)/5,$\"abcde\"", ""},

                } else if (parameterType.equals(Double.TYPE)) {
                    methodKey.append("java.lang.Double");
                } else if (parameterType.equals(Float.TYPE)) {
                    methodKey.append("java.lang.Float");
                } else if (parameterType.equals(Integer.TYPE)) {
                    methodKey.append("java.lang.Integer");
                } else if (parameterType.equals(Long.TYPE)) {

## 响应模型编码参数

你的响应模型可以具有默认值，例如：

{* ../../docs_src/response_model/tutorial004.py hl[11,13:14] *}

* `description: Union[str, None] = None` 具有默认值 `None`。
* `tax: float = 10.5` 具有默认值 `10.5`.
* `tags: List[str] = []` 具有一个空列表作为默认值： `[]`.

但如果它们并没有存储实际的值，你可能想从结果中忽略它们的默认值。

举个例子，当你在 NoSQL 数据库中保存了具有许多可选属性的模型，但你又不想发送充满默认值的很长的 JSON 响应。

### 使用 `response_model_exclude_unset` 参数

Python has support for optional "type hints" (also called "type annotations").

These **"type hints"** or annotations are a special syntax that allow declaring the <abbr title="for example: str, int, float, bool">type</abbr> of a variable.

By declaring types for your variables, editors and tools can give you better support.

  @Override
  int readInt();

  @CanIgnoreReturnValue // to skip some bytes
  @Override
  long readLong();

  @CanIgnoreReturnValue // to skip some bytes
  @Override
  float readFloat();

  @CanIgnoreReturnValue // to skip some bytes
  @Override
  double readDouble();

  @CanIgnoreReturnValue // to skip a line
  @Override
  @Nullable String readLine();