Regular Expressions 101

Pro

^start of line

Non-Capturing Group(?:(?!。).)*

*repeats the group contents below any number of times:

Negative Lookahead(?!。)

。the literal 。 (12290₁₀ / 30002₈ / 3002₁₆)

.any character (except for line terminators)

Group 1(。$)?

?repeats the group contents below at most once:

。the literal 。 (12290₁₀ / 30002₈ / 3002₁₆)

$end of line

Negative Lookahead(?!.*。)

.*any character (except for line terminators), repeated any number of times

。the literal 。 (12290₁₀ / 30002₈ / 3002₁₆)

.*any character (except for line terminators), repeated any number of times

$end of line

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

^(?:(?!。).)*(。$)?(?!.*。).*$

New

aaa。bbb。
aaa bbb。
aaa。bbb
。aaa bbb
aaa bbb

aaa。bbb。
aaa bbb。
aaa。bbb
。aaa bbb
aaa bbb