Ruby Issue Tracking System

08/29/2025

10:40 PM Ruby Feature #20163: Introduce #bit_count method on Integer

tenderlovemaking (Aaron Patterson) wrote in #note-16:
> When would you use a negative number unless it's a mistake in your code?
I don't have a strong argument. Raising an exception sounds good to me.
garrison (Garrison Jensen)

07:00 PM Ruby Feature #20163: Introduce #bit_count method on Integer

[Python ignores the sign](https://docs.python.org/3/library/stdtypes.html#int.bit_count). It seems friendlier to match that behavior than throw an exception.
``` ruby
(-x).popcount == x.popcount
```
garrison (Garrison Jensen)

01/10/2024

01:17 AM Ruby Feature #20163: Introduce #bit_count method on Integer

I like `popcount` but I also like `count_ones` because it sounds friendlier, however I have no strong preferences for the chosen name.
Also, I want to share my performance tests in case they are helpful for the discussion. As you can s... garrison (Garrison Jensen)

01/08/2024

08:50 PM Ruby Feature #20163 (Open): Introduce #bit_count method on Integer

This feature request is to implement a method called #bit_count on Integer that returns the number of ones in the binary representation of the absolute value of the integer.
```
n = 19
n.bit_count #=> 3
(-n).bit_count #=> 3
```
Thi... garrison (Garrison Jensen)