Notepad++ Selectively delete lines within a file

Question

I have a dual .srt file that looks like this:

1
00:07:14,120 --> 00:07:16,953
[French line]
[Russian line]

2
00:07:16,960 --> 00:07:19,952
[French line]
[Russian line]

3
00:07:21,240 --> 00:07:24,835
[French line]
[Russian line]

I would like to delete all the Russian lines (plus the corresponding CRLF's). Which means lines 4, 9, 14, 19, 24, 29, and so on. It's every 5 lines, starting at line 4.

I guess Notepad++'s "Find in files" should be able to do it with the right RegEx (but I'm open to any solution). Could you please help me with that? Thank you.

Answer 1

To target every nth line in non empty line sequences:

(?:(?:\R|\A).+){3}\K\R.+

See this demo at regex101 (explanation on right side)

• \A matches start of the string
• \R matches any newline sequence
• \K resets beginning of the reported match
• .+ matches one or more of any character (besides newline)
• (?: non capturing group ) {3} quantified three times

Click on "replace all" and replace with empty.
Make sure to uncheck [ ] dot matches newline in the replace dialogue.
A bit more efficient alternative with atomic group: (?>\R?.+){3}\K\R.+