Use regex to isolate information in filename

Question

I have various files that are formatted like so;

file_name_twenty_135032952.txt

where file_name_twenty is a description of the contents, and 13503295 is the id. I want two different regexes; one to get the description out of the filename, and one to get the id.

Here are some other rules that the filenames follow:

• The filename will never contains spaces, or uppercase characters
• the id will always come directly before the extension
• the id will always follow an underscore
• the description may sometimes have numbers in it; for example, in this filename: part_1_of_file_324980332.txt, part_1_of_file is the description, and 324980332 is the id.

I've been toiling for a while and can't seem to figure out a regex to solve this. I'm using python, so any limitations thereof with its regex engine follow.

Answer 1

rsplit once on an underscore and to remove the extension from id.

s = "file_name_twenty_13503295.txt"

name, id = s.rsplit(".",1)[0].rsplit("_", 1)

print(name, id)

file_name_twenty 13503295