Avoiding boilerplate by using immutable default arguments in Python - Artur Mostowski
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Avoiding boilerplate by using immutable default arguments in Python - Artur Mostowski

Hi, I recently realised one can use immutable default arguments to avoid a chain of:

def append_to(element, to=None):
    if to is None:
        to = []

at the beginning of each function with default argument for set, list, or dict.

  • m_‮f@discuss.onlineEnglish
    5·
    22 days ago

    You can use mutable default arguments now with a new syntax:

    https://peps.python.org/pep-0671/

    def bisect_right(a, x, lo=0, hi=>len(a), *, key=None):
def connect(timeout=>default_timeout):
def add_item(item, target=>[]):
def format_time(fmt, time_t=>time.time()):
    • Doccool@lemmy.world
      4·
      22 days ago

      Oh wow! This would be great I really hope it’s accepted and implemented, makes a lot of sense!

    • Narann@jlai.luEnglish
      2·
      21 days ago

      Does not seems to work on 3.12:

      Python 3.12.11 (main, Jun 29 2025, 16:18:35) [MSC v.1944 64 bit (AMD64)] on win32
>>> def toto(tata=>[]):
  File "<stdin>", line 1
    def toto(tata=>[]):
                  ^
SyntaxError: invalid syntax
      • logging_strict@programming.dev
        1·
        18 days ago

        Upvote for the sanity check.

        As the OP mentioned, this is a proposed/draft feature that may or may not ever happen.

        With these kinda posts, should start a betting pool. To put money down on whether this feature sees the light of day within an agreed upon fixed time frame.