This article explains the new features in Python 2.3. Python 2.3 was released on July 29, 2003.
The main themes for Python 2.3 are polishing some of the features
added in 2.2, adding various small but useful enhancements to the core
language, and expanding the standard library. The new object model
introduced in the previous version has benefited from 18 months of
bugfixes and from optimization efforts that have improved the
performance of new-style classes. A few new built-in functions have
been added such as sum() and enumerate(). The
in operator can now be used for substring searches (e.g.
"ab" in "abc" returns True).
Some of the many new library features include Boolean, set, heap, and date/time data types, the ability to import modules from ZIP-format archives, metadata support for the long-awaited Python catalog, an updated version of IDLE, and modules for logging messages, wrapping text, parsing CSV files, processing command-line options, using BerkeleyDB databases... the list of new and enhanced modules is lengthy.
This article doesn't attempt to provide a complete specification of the new features, but instead provides a convenient overview. For full details, you should refer to the documentation for Python 2.3, such as the Python Library Reference and the Python Reference Manual. If you want to understand the complete implementation and design rationale, refer to the PEP for a particular new feature.
See About this document... for information on suggesting changes.