*   <li><strong>Namespace Update</strong>: Changes namespace from Maven 4.0.0 to 4.1.0 for all elements</li>
 *   <li><strong>Schema Location Update</strong>: Updates xsi:schemaLocation to Maven 4.1.0 XSD</li>
 *   <li><strong>Module Conversion</strong>: Converts {@code <modules>} to {@code <subprojects>} and {@code <module>} to {@code <subproject>}</li>
 *   <li><strong>Model Version Update</strong>: Updates {@code <modelVersion>} to 4.1.0</li>
 * </ol>
 *

* <dfn title="also known as: serialization, parsing, marshalling">Conversion</dfn> of input data: coming from the network to Python data and types. Reading from:
    * JSON.
    * Path parameters.
    * Query parameters.
    * Cookies.
    * Headers.
    * Forms.
    * Files.

func isASCII(s string) bool {
	for _, c := range s {
		if c >= 0x80 || c == 0x00 {
			return false
		}
	}
	return true
}

// toASCII converts the input to an ASCII C-style string.
// This is a best effort conversion, so invalid characters are dropped.
func toASCII(s string) string {
	if isASCII(s) {
		return s
	}
	b := make([]byte, 0, len(s))
	for _, c := range s {
		if c < 0x80 && c != 0x00 {
			b = append(b, byte(c))

ENV BAZEL_VS "C:\Program Files\Microsoft Visual Studio\2022\BuildTools"
ENV BAZEL_VC "C:\Program Files\Microsoft Visual Studio\2022\Community\VC"

# Environment variables to prevent auto-conversion of Linux-like paths to Windows paths.
# This is necessary as some paths end up invalid/mangled.
ENV MSYS_NO_PATHCONV 1
ENV MSYS2_ARG_CONV_EXCL *

        descrField.setAccessible(true);
        String descr = (String) descrField.get(null);

        assertEquals("WrLeh\u0000B13BWz\u0000", descr);

        // Verify ASCII conversion
        byte[] descrBytes = descr.getBytes("ASCII");
        assertNotNull(descrBytes);
        assertEquals(13, descrBytes.length); // WrLeh(5) + null(1) + B13BWz(6) + null(1) = 13
    }

    @Test

        final String text = value.trim();

        final Class<?> rawType = toType.getRawType();
        if (rawType.isAssignableFrom(String.class)) {
            return text; // compatible type => no conversion needed
        }

        // use temporary Key as quick way to auto-box primitive types into their equivalent object types
        final TypeLiteral<?> boxedType =

{* ../../docs_src/path_params/tutorial002_py310.py hl[7] *}

本例把 `item_id` 的类型声明为 `int`。

/// check | 检查

类型声明将为函数提供错误检查、代码补全等编辑器支持。

///

## 数据<dfn title="也称为：序列化、解析、编组">转换</dfn> { #data-conversion }

运行示例并访问 [http://127.0.0.1:8000/items/3](http://127.0.0.1:8000/items/3)，返回的响应如下：

```JSON
{"item_id":3}
```

/// check | 检查

注意，函数接收并返回的值是 `3`（ `int`），不是 `"3"`（`str`）。

* <dfn title="also known as: serialization, parsing, marshalling">Conversion</dfn> of input data: coming from the network to Python data and types. Reading from:
    * JSON.
    * Path parameters.
    * Query parameters.
    * Cookies.
    * Headers.
    * Forms.
    * Files.

  // TODO: IdentityHashMap, AbstractMap

  private static Map<String, String> toHashMap(Entry<String, String>[] entries) {
    return populate(new HashMap<String, String>(), entries);
  }

  // TODO: call conversion constructors or factory methods instead of using
  // populate() on an empty map
  @CanIgnoreReturnValue
  private static <T, M extends Map<T, String>> M populate(M map, Entry<T, String>[] entries) {

That means that any value read in Python from an environment variable will be a `str`, and any conversion to a different type or any validation has to be done in code.

## Pydantic `Settings` { #pydantic-settings }