Regular Expressions 101

Explanation

Pro

Group 1([^\d]|(?<!\d)\d(?!\d{3}(?!\d))\d*)?

?repeats the group contents below at most once:

1st Alternative[^\d]

Negated Character Class[^\d]

\da Unicode decimal digit

2nd Alternative(?<!\d)\d(?!\d{3}(?!\d))\d*

Negative Lookbehind(?<!\d)

\da Unicode decimal digit

Negative Lookahead(?!\d{3}(?!\d))

\d{3}a Unicode decimal digit, repeated exactly 3 times

Negative Lookahead(?!\d)

\da Unicode decimal digit

\d*a Unicode decimal digit, repeated any number of times

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]|(?<!\d)\d(?!\d{3}(?!\d))\d*)?

New

Film_relase_date:1970_films_by_20th_Century_Fox
Film_relase_date:19720_films_by_20th_Century_Fox
Film_relase_date:197_films_by_20th_Century_Fox

Film_relase_date:1970_films_by_20th_Century_Fox
Film_relase_date:19720_films_by_20th_Century_Fox
Film_relase_date:197_films_by_20th_Century_Fox