# Python 类型提示简介

**Python 3.6+ 版本**加入了对"类型提示"的支持。

这些**"类型提示"**是一种新的语法（在 Python 3.6 版本加入）用来声明一个变量的<abbr title="例如：str、int、float、bool">类型</abbr>。

通过声明变量的类型，编辑器和一些工具能给你提供更好的支持。

这只是一个关于 Python 类型提示的**快速入门 / 复习**。它仅涵盖与 **FastAPI** 一起使用所需的最少部分...实际上只有很少一点。

整个 **FastAPI** 都基于这些类型提示构建，它们带来了许多优点和好处。

但即使你不会用到 **FastAPI**，了解一下类型提示也会让你从中受益。

/// note

如果你已经精通 Python，并且了解关于类型提示的一切知识，直接跳到下一章节吧。

///

## 动机

让我们从一个简单的例子开始：

Sie können für Typ Deklarationen auch `str`, `float`, `bool` und viele andere komplexe Datentypen verwenden.

Mehrere davon werden wir in den nächsten Kapiteln erkunden.

## Die Reihenfolge ist wichtig

}

// Compares all the bytes returned by the given readers. Any Read
// errors cause a `false` result. A string describing the error is
// also returned.
func cmpReaders(r1, r2 io.Reader) (bool, string) {
	bufLen := 32 * 1024
	b1, b2 := make([]byte, bufLen), make([]byte, bufLen)
	for i := 0; true; i++ {
		n1, e1 := io.ReadFull(r1, b1)
		n2, e2 := io.ReadFull(r2, b2)
		if n1 != n2 {

	for _, table := range parts {
		// If table is not empty, get table name from the first line
		lines := strings.Split(strings.Trim(table, "\n"), "\n")
		lines = slices.Filter(lines, func(line string) bool {
			return line != "iptables-save" && line != "ip6tables-save"
		})

		if len(lines) >= 1 && strings.HasPrefix(lines[0], "* ") {
			tableName := lines[0][2:]
			lines = append(lines, "COMMIT")

			// the parser is more liberal than what USTAR actually permits.
			notASCII := func(r rune) bool { return r >= 0x80 }
			if bytes.IndexFunc(tr.blk[:], notASCII) >= 0 {
				hdr.Format = FormatUnknown // Non-ASCII characters in block.
			}
			nul := func(b []byte) bool { return int(b[len(b)-1]) == 0 }
			if !(nul(v7.size()) && nul(v7.mode()) && nul(v7.uid()) && nul(v7.gid()) &&

from typing import Union

from fastapi import FastAPI
from pydantic import BaseModel

app = FastAPI()


class Item(BaseModel):
    name: str
    price: float
    is_offer: Union[bool, None] = None


@app.get("/")
def read_root():
    return {"Hello": "World"}


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

  optional string concurrencyPolicy = 3;

  // This flag tells the controller to suspend subsequent executions, it does
  // not apply to already started executions.  Defaults to false.
  // +optional
  optional bool suspend = 4;

  // Specifies the job that will be created when executing a CronJob.
  optional JobTemplateSpec jobTemplate = 5;

  // The number of successful finished jobs to retain. Value must be non-negative integer.

	// erasure reconstruction in this test
	offDisks int

	// bad disks are online disks which return errors
	badDisks, badStaleDisks int

	blocksize, size int64
	algorithm       BitrotAlgorithm
	shouldFail      bool
}{
	{dataBlocks: 2, disks: 4, offDisks: 1, badDisks: 0, badStaleDisks: 0, blocksize: int64(blockSizeV2), size: oneMiByte, algorithm: SHA256, shouldFail: false},                   // 0

	args             []string

	// Typically use one of the three
	expectedOutput string // Expected constant output
	expectedString string // String output is expected to contain

	wantException bool
}

func TestProxyConfig(t *testing.T) {
	loggingConfig := map[string][]byte{
		"details-v1-5b7f94f9bc-wp5tb": util.ReadFile(t, "../writer/envoy/logging/testdata/logging.txt"),
		"httpbin-794b576b6c-qx6pf":    []byte("{}"),

Параметры функции распознаются следующим образом:

* Если параметр также указан в **пути**, то он будет использоваться как параметр пути.
* Если аннотация типа параметра содержит **примитивный тип** (`int`, `float`, `str`, `bool` и т.п.), он будет интерпретирован как параметр **запроса**.
* Если аннотация типа параметра представляет собой **модель Pydantic**, он будет интерпретирован как параметр **тела запроса**.

/// note | "Заметка"