Python 3.7 的新功能 ¶

摘要 – 发行亮点 ¶

新句法特征：

• PEP 563 , postponed evaluation of type annotations.

Backwards incompatible syntax changes:

• async and await are now reserved keywords.

新的库模块：

• contextvars : PEP 567 – Context Variables

• dataclasses : PEP 557 – Data Classes

• importlib.resources

新的内置特征：

• PEP 553 ，新 breakpoint() 函数。

Python data model improvements:

• PEP 562 , customization of access to module attributes.

• PEP 560 , core support for typing module and generic types.

• the insertion-order preservation nature of dict 对象 has been declared to be an official part of the Python language spec.

Significant improvements in the standard library:

• The asyncio module has received new features, significant usability and performance improvements .

• The time module gained support for functions with nanosecond resolution .

CPython 实现改进：

• Avoiding the use of ASCII as a default text encoding:

  • PEP 538 , legacy C locale coercion

  • PEP 540 , forced UTF-8 runtime mode

• PEP 552 , deterministic .pycs

• New Python Development Mode

• PEP 565 , improved DeprecationWarning handling

C API 改进：

• PEP 539 ，用于线程局部存储的新 C API

文档编制改进：

• PEP 545 , Python documentation translations

• New documentation translations: 日语 , 法语 ，和 韩语 .

This release features notable performance improvements in many areas. The 优化 section lists them in detail.

For a list of changes that may affect compatibility with previous Python releases please refer to the 移植到 Python 3.7 章节。

新特征 ¶

class C:
    @classmethod
    def from_string(cls, source: str) -> C:
        ...
    def validate_b(self, obj: B) -> bool:
        ...
class B:
    ...