How can I edit a string with a regular expression in Notepad++?

Question

Regular Expressions

How to edit a document of this kind through regular expressions? I've tried everything, it doesn't work.
Document:

00257--строка а
00258--строка - а а 
00259--аапап
00260--апа3увва
00261--вавав3уау
00262--вавапвп3пкп

You need to leave only what goes up to --. Delete the rest.

Answer 1

(-.+)$

If you want to leave the hyphens, just replace with "--".
In general, there are +100500 more methods.