Regular Expressions 101

Group 1(\n\n|\A\n?)

1st Alternative\n\n

\na line-feed (newline) character (ASCII 10)

2nd Alternative\A\n?

\Astart of string

\n?optionally matches a line-feed (newline) character (ASCII 10)

-the literal - (45₁₀ / 55₈ / 2D₁₆)

\s*any whitespace character, repeated any number of times

Negative Lookahead(?!.*\n-)

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

\na line-feed (newline) character (ASCII 10)

-the literal - (45₁₀ / 55₈ / 2D₁₆)

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.

Search reference

Regular Expression

(\n\n|\A\n?)-\s*(?!.*\n-)

New

- Lovely day.

- Lovely day-night cycle.

- Lovely day.
Isn't it?

- lovely day - isn't it?

- Lovely day -
isn't it?

Here are few example strings where leading dash character(s) should be retained (note the 2nd example, it might be tricky):

- Lovely day.
- Yeah, isn't it?

Lovely day.
- Yeah, isn't it?

- lovely day - isn't it?
- Yes.

- Lovely day for a -
- Walk?

Regular Expression

Extraction