}

func dropRune(text string) (res string, ok bool) {
	r := []rune(text)
	if len(r) == 0 {
		return "", false
	}
	return string(r[1:]), true
}

func evalSQLSubstring(s string, startIdx, length int) (res string, err error) {
	rs := []rune(s)

	// According to s3 document, if startIdx < 1, it is set to 1.
	if startIdx < 1 {
		startIdx = 1
	}

	if startIdx > len(rs) {
		startIdx = len(rs) + 1

これを行うには、`return`の代わりに`yield`を使い、その後に追加のステップを書きます。

/// tip | 豆知識

`yield`は必ず一度だけ使用するようにしてください。

///

/// info | 情報

これを動作させるには、**Python 3.7** 以上を使用するか、**Python 3.6** では"backports"をインストールする必要があります:

```
pip install async-exit-stack async-generator
```

In this case, this dependency expects:

* An optional query parameter `q` that is a `str`.
* An optional query parameter `skip` that is an `int`, and by default is `0`.
* An optional query parameter `limit` that is an `int`, and by default is `100`.

And then it just returns a `dict` containing those values.

/// info

FastAPI added support for `Annotated` (and started recommending it) in version 0.95.0.

# Модель Pydantic
class User(BaseModel):
    id: int
    name: str
    joined: date
```

Это можно использовать так:

```Python
my_user: User = User(id=3, name="John Doe", joined="2018-07-19")

second_user_data = {
    "id": 4,
    "name": "Mary",
    "joined": "2018-11-30",
}

my_second_user: User = User(**second_user_data)
```

/// info | Информация

`**second_user_data` означает:

		return
	}

	vars := mux.Vars(r)
	v := vars["pool"]
	byID := vars["by-id"] == "true"

	pools := strings.Split(v, ",")
	poolIndices := make([]int, 0, len(pools))

	for _, pool := range pools {
		var idx int
		if byID {
			var err error
			idx, err = strconv.Atoi(pool)
			if err != nil {
				// We didn't find any matching pools, invalid input

//
//	type User struct {
//	  Toys []Toy `gorm:"polymorphic:Owner;"`
//	}
//	type Pet struct {
//	  Toy Toy `gorm:"polymorphic:Owner;"`
//	}
//	type Toy struct {
//	  OwnerID   int
//	  OwnerType string
//	}
func (schema *Schema) buildPolymorphicRelation(relation *Relationship, field *Field) {
	polymorphic := field.TagSettings["POLYMORPHIC"]

	relation.Polymorphic = &Polymorphic{

///

## 다중 모델

아래는 비밀번호 필드와 해당 필드가 사용되는 위치를 포함하여, 각 모델들이 어떤 형태를 가질 수 있는지 전반적인 예시입니다:

{* ../../docs_src/extra_models/tutorial001_py310.py hl[7,9,14,20,22,27:28,31:33,38:39] *}


/// info | 정보

Pydantic v1에서는 해당 메서드가 `.dict()`로 불렸으며, Pydantic v2에서는 `.model_dump()`로 이름이 변경되었습니다. `.dict()`는 여전히 지원되지만 더 이상 권장되지 않습니다.

				return
			}
		}
	}
	o = bts
	return
}

// Msgsize returns an upper bound estimate of the number of bytes occupied by the serialized message
func (z *WalkDirOptions) Msgsize() (s int) {

/// tip | 提示

不必为你使用的所有标签都添加元数据。

///

### 使用你的标签

将 `tags` 参数和*路径操作*（以及 `APIRouter`）一起使用，将其分配给不同的标签：

{* ../../docs_src/metadata/tutorial004.py hl[21,26] *}

/// info | 信息

阅读更多关于标签的信息[路径操作配置](path-operation-configuration.md#tags){.internal-link target=_blank}。

///

### 查看文档

如果你现在查看文档，它们会显示所有附加的元数据：

<img src="/img/tutorial/metadata/image02.png">

### 标签顺序

	// Should never contain a slash.
	FilterPrefix string

	// ForwardTo will forward to the given object path.
	ForwardTo string

	// Limit the number of returned objects if > 0.
	Limit int

	// DiskID contains the disk ID of the disk.
	// Leave empty to not check disk ID.
	DiskID string
}

// supported FS for Nlink optimization in readdir.
const (
	xfs  = "XFS"
	ext4 = "EXT4"
)