# Introduction aux Types Python

Python supporte des annotations de type (ou *type hints*) optionnelles.

Ces annotations de type constituent une syntaxe spéciale qui permet de déclarer le <abbr title="par exemple : str, int, float, bool">type</abbr> d'une variable.

En déclarant les types de vos variables, cela permet aux différents outils comme les éditeurs de texte d'offrir un meilleur support.

  @Override
  void writeShort(int v);

  @Override
  void writeChar(int v);

  @Override
  void writeInt(int v);

  @Override
  void writeLong(long v);

  @Override
  void writeFloat(float v);

  @Override
  void writeDouble(double v);

  @Override
  void writeChars(String s);

  @Override
  void writeUTF(String s);

  /**

            ],
            "msg": "value is not a valid integer",
            "type": "type_error.integer"
        }
    ]
}
```

这是因为路径参数 `item_id` 的值 （`"foo"`）的类型不是 `int`。

值的类型不是 `int ` 而是浮点数（`float`）时也会显示同样的错误，比如： <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 | 检查

**FastAPI** 使用 Python 类型声明实现了数据校验。

注意，上面的错误清晰地指出了未通过校验的具体原因。

      "input": "foo"
    }
  ]
}
```

porque o parâmetro de path `item_id` tinha o valor `"foo"`, que não é um `int`.

O mesmo erro apareceria se você fornecesse um `float` em vez de um `int`, como em: <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 | Verifique

		f, err := strconv.ParseFloat(strings.TrimSpace(x), 64)
		if err != nil {
			return 0, errCastFailure("could not parse as float")
		}
		return f, nil
	case []byte:
		f, err := strconv.ParseFloat(strings.TrimSpace(string(x)), 64)
		if err != nil {
			return 0, errCastFailure("could not parse as float")
		}
		return f, nil
	default:
		return 0, errUnsupportedCast(v.GetTypeString(), castFloat)
	}
}

            throws NoRepositoryConnectorException {
        return new TestRepositoryConnector(repository);
    }

    @Override
    public float getPriority() {
        return 0;
    }

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.

        Map<String, Object> configProperties =
                systemSessionFactory.newRepositorySession(request).getConfigProperties();
        assertEquals(String.valueOf(Float.MAX_VALUE), configProperties.get("aether.priority.FileTransporterFactory"));
        assertEquals(String.valueOf(Float.MAX_VALUE), configProperties.get("aether.priority.ApacheTransporterFactory"));
        properties.remove("maven.resolver.transport");

        // wagon

		{Name: "FLOAT32", DBName: "ffloat32", BindNames: []string{"FLOAT32"}, DataType: schema.Float, Creatable: true, Updatable: true, Readable: true, Size: 32, Tag: `gorm:"column:ffloat32"`},
		{Name: "FLOAT64", DBName: "ffloat64", BindNames: []string{"FLOAT64"}, DataType: schema.Float, Creatable: true, Updatable: true, Readable: true, Size: 64, Tag: `gorm:"column:ffloat64"`},

    * `price` adında zorunlu bir parametre olup olmadığını ve varsa tipinin `float` olup olmadığını kontol edecek.
    * `is_offer` adında opsiyonel bir parametre olup olmadığını ve varsa tipinin `float` olup olmadığını kontol edecek.
    * Bunların hepsi en derin JSON nesnelerinde bile çalışacak.