Comment on Python Performance: Why 'if not list' is 2x Faster Than Using len()

• sirber@lemmy.ca ⁨4⁩ ⁨days⁩ ago

  I think you missed the joke 😅

  source

  • PattyMcB@lemmy.world ⁨4⁩ ⁨days⁩ ago

    I thought it was funny!

    source
• gravitas_deficiency@sh.itjust.works ⁨4⁩ ⁨days⁩ ago

  You’re checking if mylist is falsey. Sometimes that’s the same as checking if it’s empty, if it’s actually a list, but that’s not guaranteed.

  source

  • JasonDJ@lemmy.zip ⁨4⁩ ⁨days⁩ ago

    Doesn’t Python treat all empty iterables as false tho? This isn’t unique to python, is it? (though I’m not a programmer…just a dude who writes scripts every now and then)

    source

    • gravitas_deficiency@sh.itjust.works ⁨4⁩ ⁨days⁩ ago

      My point is that the second statement you presented can have the effect of evaluating emptiness of a Sequence (note: distinct from an Iterable), but that only holds true if the target of the conditional IS a sequence. I’m underlining the semantic difference that was elided as a result of falsey evaluation.

      source

      • JasonDJ@lemmy.zip ⁨4⁩ ⁨days⁩ ago

        Ok, help a noob out. What is the difference between a sequence and an iterable? Is a sequence immutable, like a tuple?

        source

        • -> View More Comments
    • BlackRoseAmongThorns@slrpnk.net ⁨3⁩ ⁨days⁩ ago

      Not really, generators have weird truthiness, i don’t remember if they evaluate to true or false, but they cannot be checked for emptiness so they default to either always true or always false.

      source