Feature request: Allows the number of uniform breaks (n.breaks) to be supplied as a parameter after setting scale='free_y' in the facet_* function

[Breeze-Hu]

Happy New Year!

I recently encountered a need to use facets (facet_*) to present different types of data, where the values in each facet differ significantly in order of magnitude (e.g., n * 10, n * 100, etc.). To make the y-axis labeling more appropriate, I used scale = 'free_y'.

However, I noticed that the n.breaks parameter in scale_y_continuous does not set the exact number of axis breaks as expected—it adjusts them, but not to the precise quantity specified. This inconsistency makes it challenging to maintain uniformity and clarity across all faceted plots.

Would it be possible to enhance the functionality to allow setting the exact number of axis breaks (n.breaks in facet_*) when using scale = 'free_y'? This feature would greatly improve the visual consistency and readability of faceted plots.

Best regards,
Hu

[teunbrand]

You can use a function in scale_y_continuous(breaks) to change the breaks algorithm for different limits.
I think all break functions that come with {scales} prefer pretty breaks over an exact number of breaks, but you are welcome to devise your own break algorithm. Because of this, I don't think there is anything more that ggplot2 should do in this case.
If you want an implementation of a breaks function for an exact number of breaks, that would belong in the {scales} package.

[Breeze-Hu]

Okay. I can understand the design concept. Thank you very much.