Regular Expressions 101

Pro

Positive Lookbehind(?<=-)

-the literal - (45₁₀ / 55₈ / 2D₁₆)

Condition(?(?=\d{2})|(?'oneLetter'\d))

Uses the first branch if the lookaround matches

Positive Lookahead(?=\d{2})

\d{2}a digit, repeated exactly 2 times

If the condition is true, match this branch: — matches an empty string

Otherwise, match this branch:(?'oneLetter'\d)

Group oneLetter(?'oneLetter'\d)

\da digit

Positive Lookahead(?=\D)

\Dany character that's not a digit

Global pattern flags

g modifier: global. Finds all matches instead of stopping after the first

m modifier: multiline. Causes ^ and $ to match the start and end of each line, not only the start and end of the string

Detailed match information will be displayed here automatically.

25 tokens

(?<=-)(?(?=\d{2})|(?'oneLetter'\d))(?=\D)

2020-7-3; blah.mp4
2022-08-03_blah.mp4
2013-04-03-20-34-08; blah.mp4

2020-7-3; blah.mp4
2022-08-03_blah.mp4
2013-04-03-20-34-08; blah.mp4