Discover why 'if not mylist' is twice as fast as 'len(mylist) == 0' by examining CPython's VM instructions and object memory access patterns.
      • sugar_in_your_tea@sh.itjust.works
        0·
        5 days ago

        def some_func(*args, kwarg=[])

        Don’t do this:

        def fun(l=[]):
    l.append(len(l))
    return l

fun()  # [0]
fun()  # [0, 1]
fun(l=[])  # [0]
fun()  # [0, 1, 2]
fun(l=None)  # raise AttributeError or TypeError if len(l) comes first

        This can be downright cryptic if you’re passing things dynamically, such as:

        def caller(*args, **kwargs):
    fun(*args, **kwargs)

        It’s much safer to do a simple check at the beginning:

        if not l: 
    l = []
          • logging_strict@programming.dev
            0·
            5 days ago

            Oh no a stray None! Take cover …

            Robust codebase should never fail from a stray None

            Chaos testing is specifically geared towards bullet proofing code against unexpected param types including None.

            The only exception is for private support function for type specific checking functions. Where it’s obviously only for one type ever.

            We live in clownworld, i’m a clown and keep the company of shit throwing monkeys.