What's new in Python 3.13 ?

What's new in Python 3.13 ?

General Improvements:

  • Interactive Interpreter: Enhanced with color support, multiline editing, interactive help, and history browsing.

  • Error Messages: Improved with better colorization and more informative messages for common mistakes.

  • Incremental Garbage Collection: Reduced pause times for larger heaps.

  • Performance: Introduction of a basic JIT compiler, although currently disabled by default.

Typing Enhancements:

  • PEP 696: Type parameters now support defaults.

  • PEP 702: Deprecation warnings can now be marked in the type system.

  • PEP 742: Introduction of typing.TypeIs for more intuitive type narrowing behavior.

  • PEP 705: Addition of typing.ReadOnly for marking items in TypedDict as read-only.

Concurrency and Threading:

  • Free-threading Support (PEP 703): Experimental support for disabling the Global Interpreter Lock (GIL), enabling better utilization of multicore processors.

Platform Support:

  • iOS Support (PEP 730): iOS is now officially supported.

  • Upcoming Android Support (PEP 738).

Library and Module Updates:

  • Deprecated and Removed Modules (PEP 594): Removal of 19 deprecated modules including cgi, nntplib, pipes, and telnetlib.

  • New Typing Features: Enhanced support for typing parameters, deprecations, and narrowing behavior.

Standard Library Enhancements:

  • Defined Mutation Semantics forlocals() (PEP 667): Standardizes behavior for mutating locals() in various scopes.

  • Updated Release Schedule (PEP 602): Python 3.13 and later versions will have two years of full support followed by three years of security fixes.

Other Notable Features:

  • Better Interactive Shell: New REPL features include colorized prompts, multiline editing, and command history browsing.

  • Optimizedstr.replace(): Allowing the count argument to be a keyword for better flexibility.

Experimental Features:

  • JIT Compiler (PEP 744): Added but disabled by default; expected to improve in future releases.

  • Free-threaded CPython (PEP 703): Allows running without the GIL when built with --disable-gil.

Miscellaneous Improvements:

  • Improvedlocals() Handling: Ensures debuggers and tools can reliably update local variables during optimized scopes.

  • New Typing Constructs:typing.ReadOnly, typing.NoDefault, and other improvements for type checking and annotations.

These updates highlight Python 3.13's focus on enhancing the interactive development experience, improving performance, expanding platform support, and refining the typing system for more robust and clear code.