3 ms·

return '⊥' what's this?

jbaber 2y ago
In some symbolic logic classes, that character "bottom" represents "false" ad flipped "top" means true. Don't know what they're getting at in the code, though.
- dentemple 2y ago
  Once again proving the need for comments in code. Especially for comments that are more useful than "initialize parameters"
- hollerith 2y ago
  >In some symbolic logic classes, that character "bottom" represents "false" That's unfortunate, because in the study of computer programming languages, it means "undefined" (raise an error).
  - tsss 2y ago
    Not always. It is also the uninhabited bottom type.
    - hollerith 2y ago
      My point is that there is a difference between a Python function's returning false and the function's raising an error, and sometimes the difference really matters, so it would be regrettable if logic teachers actually did use ⊥ to mean false because programming-language theorists use it to mean something whose only reasonable translation in the domain of practical programming is to raise an error. I have no idea what your point is.
  - deleted 2y ago
    [deleted]
martinsnow 2y ago
An easy way to identify who copies code without understanding it.
- mudiadamz 2y ago
  You can just replace it with something like: print ('Invalid thresh or something')
  - martinsnow 2y ago
    This however looks scary so an innocent copy/paste programmer wouldn't touch it.
deleted 2y ago
[deleted]
rcarmo 2y ago
An error condition. I decided to do away with it and take a small hit on the error by assuming the chances of the trimmed set being equal to the threshold are very small and that the error condition is effectively doing nothing. I also changed the logic from == to >= to trigger unfailingly, and pass in the "window"/threshold to allow my code to work without internal awareness of the length of the iterable: from random import random def estimate_uniques(iterable, window_size=100): p = 1 seen = set() for i in iterable: if i not in seen: seen.add(i) if random() > p: seen.remove(i) if len(seen) >= window_size: seen = {s for s in seen if random() < 0.5} p /= 2 return int(len(seen) / p) I also didn't like the possible "set thrashing" when an item is removed and re-added for high values of p, so I inverted the logic. This should work fine for any iterable.
- deleted 2y ago
  [deleted]

In some symbolic logic classes, that character "bottom" represents "false" ad flipped "top" means true. Don't know what they're getting at in the code, though.

dentemple 2y ago
Once again proving the need for comments in code. Especially for comments that are more useful than "initialize parameters"
hollerith 2y ago
>In some symbolic logic classes, that character "bottom" represents "false" That's unfortunate, because in the study of computer programming languages, it means "undefined" (raise an error).
- tsss 2y ago
  Not always. It is also the uninhabited bottom type.
  - hollerith 2y ago
    My point is that there is a difference between a Python function's returning false and the function's raising an error, and sometimes the difference really matters, so it would be regrettable if logic teachers actually did use ⊥ to mean false because programming-language theorists use it to mean something whose only reasonable translation in the domain of practical programming is to raise an error. I have no idea what your point is.
- deleted 2y ago
  [deleted]

martinsnow 2y ago

An easy way to identify who copies code without understanding it.

mudiadamz 2y ago
You can just replace it with something like: print ('Invalid thresh or something')
- martinsnow 2y ago
  This however looks scary so an innocent copy/paste programmer wouldn't touch it.

deleted 2y ago

[deleted]

rcarmo 2y ago

An error condition. I decided to do away with it and take a small hit on the error by assuming the chances of the trimmed set being equal to the threshold are very small and that the error condition is effectively doing nothing. I also changed the logic from == to >= to trigger unfailingly, and pass in the "window"/threshold to allow my code to work without internal awareness of the length of the iterable: from random import random def estimate_uniques(iterable, window_size=100): p = 1 seen = set() for i in iterable: if i not in seen: seen.add(i) if random() > p: seen.remove(i) if len(seen) >= window_size: seen = {s for s in seen if random() < 0.5} p /= 2 return int(len(seen) / p) I also didn't like the possible "set thrashing" when an item is removed and re-added for high values of p, so I inverted the logic. This should work fine for any iterable.

deleted 2y ago
[deleted]