Ruby already provides the ability to find the greatest common factor (gcf) of two integers. What if we could determine the greatest common factor across a whole array of integers? Now we can.
I’ve just released greatest_common_factor on github.
Here is a sample of what you can do with it:
[12,16,8,40].greatest_common_factor => 4
[12,16,8,40].gcf => 4
[12,16,8,40].factored_by_gcf => [3, 4, 2, 10]
Update:
You can now also specify a tolerance for greatest common factor calculations. In many cases, you’ll have data that is so close to having a common factor, but not perfectly.
Let’s see how changing the tolerance can provide a greatest common factor that’s close enough (or as close as you let it be, anyway).
[12,16,8,41].greatest_common_factor => nil
# but, if we add a tolerance of 1
[12,16,8,41].greatest_common_factor(1) => 4
[11,15,9,41].greatest_common_factor => nil
[11,15,9,41].greatest_common_factor(1) => 2
Enjoy!