Regular Expressions 101

Pro

^start of line

Group ALL(?<ALL>[^H\n]*(?:H(?!-\d{4}\b)[^H\n]*)*(?<ID>H-\d{4}\b)?.*)

Negated Character Class[^H\n]*

*matches any number of characters outside the set below:

Hthe literal H (72₁₀ / 110₈ / 48₁₆) (case sensitive)

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

Non-Capturing Group(?:H(?!-\d{4}\b)[^H\n]*)*

*repeats the group contents below any number of times:

Hthe literal H (72₁₀ / 110₈ / 48₁₆) (case sensitive)

Negative Lookahead(?!-\d{4}\b)

-the literal - (45₁₀ / 55₈ / 2D₁₆)

\d{4}a digit, repeated exactly 4 times

\ban ASCII word boundary

Negated Character Class[^H\n]*

*matches any number of characters outside the set below:

Hthe literal H (72₁₀ / 110₈ / 48₁₆) (case sensitive)

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

Group ID(?<ID>H-\d{4}\b)?

?repeats the group contents below at most once:

H-the literal text H- (case sensitive)

\d{4}a digit, repeated exactly 4 times

\ban ASCII word boundary

.*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

^(?<ALL>[^H\n]*(?:H(?!-\d{4}\b)[^H\n]*)*(?<ID>H-\d{4}\b)?.*)$

New

Sample line with H-5722 id
Sample line without id
a Honululu line

Sample line with H-5722 id
Sample line without id
a Honululu line