Grasshopper Grouping Objects by Abbreviated layer name

[Michael31 (Michael)]

Hello,
I have set up the script that is allowing me to calculate the total area of the objects on each layer, but I want to be able to simplify the Layer Name to just the first 3 characters, so that all the 01A layers are calculated together, all the 01B are calculated together, etc.

This would allow me to keep my layer structure in Rhino, but just change its 3 character designation to change the way it is calculated in the final areas.

[Gijs (Gijs de Zwart)]

You could use a small python script to filter on the first 3 characters, then use that to create sets and based on those sets, partition the original list of layers: