env.workspace - how to navigate "up" one folder?

[JT2]

I am familiar with setting the env.workspace parameter in arcpy. That allows me to work within subfolders of the workspace, eg:

layer = arcpy.mapping.Layer("Sub\Test.shp")

But how do I do the opposite, ie go up one level in the folder tree?

This doesn't work:

layer = arcpy.mapping.Layer("..\Test.shp")

Is there an easy way to go up a level from the workspace path? Or is it not possible?

Thanks

[MathewCoyle · Accepted solution]

I don't think you can, how you envision it in any case. You can walk your workspace back one level and use the full path as a variable though.

up_one_dir = arcpy.env.workspace.rsplit(os.sep, 1)[0]