You can use the functions provided by os.path for handling pathnames independendly from a platform.

import bpy
import os

filepath = bpy.data.filepath
directory = os.path.dirname(filepath)
print(directory)

You can use the functions provided by os.path for handling pathnames independendly from a platform.

import bpy
import os

filepath = bpy.data.filepath
directory = os.path.dirname(filepath)
print(directory)

To add a file to the basename you could use os.path.join:

newfile_name = os.path.join( directory , "newfile.blend")

You can use the functions provided by os.path for handling pathnames independendly from a platform.

import bpy
import os

file = bpy.data.filepath
directory = os.path.dirname(file)
print( directory )

You can use the functions provided by os.path for handling pathnames independendly from a platform.

import bpy
import os

filepath = bpy.data.filepath
directory = os.path.dirname(filepath)
print(directory)