metricsKeys elements

Is there a way to access the elements of metrics keys other than via .replace() or regular expressions? I ask, because I find no way to properly extract glyph names like “Che-cy” when trying to extract the figures, mathematical operators and floating point [0-9-+* /=.] from the keys. The only thing I can think of is to check further, if after an operator there is a letter again and in this case leave the operator. But since Glyphs can handle key like “C=Che-cy*1.2” i assume there could be some more legit way to catch the “Che-cy” itself?

You search for numbers and periods. If you only find those on the right of a hyphen, it is a factor, otherwise it is a part of the name.

What I thought. thanks.