Python Versions

Important (to me) changes by version:

3.11

• SPEED!

• tomllib (read-only)

• PEP 657: Fine-grained error locations in tracebacks

• PEP 594: Many legacy standard library modules have been deprecated and will be removed in Python 3.13

3.10

• match pattern matching (which I have not yet looked at)

• parenthesized context managers (for formatting ease, no semantic difference)

• Deprecate distutils module.

3.9

• dict union operator

• string methods to remove prefixes and suffixes.

• zoneinfo module

3.8

• walrus operator (“:=”)

• f-strings add “=” support

• Positional-only parameters: “new function parameter syntax / to indicate that some function parameters must be specified positionally and cannot be used as keyword arguments. “ - def f(a, b, /, c, d, *, e, f): means that a and b can only be passed by position and not by keyword.

• asyncio.run

3.7

• context vars Context variables are conceptually similar to thread-local variables. Unlike TLS, context variables support asynchronous code correctly.

• Data classes

3.6

• asyncio module is no longer provisional

• f-strings

• underscores in numeric literals

• secrets module provide an obvious way to reliably generate cryptographically strong pseudo-random values suitable for managing secrets, such as account authentication, tokens, and similar.

3.5

• can use multiple “*” and “**” unpacking operators

• new typing module

• new os.scandir() function

• new subprocess.run() function

3.4

• new enum module

• new pathlib module (provisional)

• new ensurepip module

• provisional asyncio module

3.3

• yield from expression

• The u’unicode’ syntax is accepted again for str objects.

• new unittest.mock module

• new venv module and pyvenv script

• implicit namespace packages

3.2

• new argparse module

• logging.config.dictConfig()

• major redesign of how bytecode is cached in files

• PYTHONWARNINGS <https://docs.python.org/3/using/cmdline.html#envvar-PYTHONWARNINGS> env var

• functools.lru_cache()