Regular Expressions 101

1st Alternative^\d{5}(?![\d-])

^start of line

\d{5}a digit, repeated exactly 5 times

Negative Lookahead(?![\d-])

Character Class[\d-]

\da digit

-the literal - (45₁₀ / 55₈ / 2D₁₆)

2nd Alternative^\d{5}(?:-\d{4})(?!\d)

^start of line

\d{5}a digit, repeated exactly 5 times

Non-Capturing Group(?:-\d{4})

-the literal - (45₁₀ / 55₈ / 2D₁₆)

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

Negative Lookahead(?!\d)

\da digit

3rd Alternative(?<!\d)\d{5}(?:-\d{4})(?:[\r\n])

Negative Lookbehind(?<!\d)

\da digit

\d{5}a digit, repeated exactly 5 times

Non-Capturing Group(?:-\d{4})

-the literal - (45₁₀ / 55₈ / 2D₁₆)

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

Non-Capturing Group(?:[\r\n])

Character Class[\r\n]

\ra carriage return (ASCII 13)

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

4th Alternative(?<![\d-])\d{5}(?:[\r\n])

Negative Lookbehind(?<![\d-])

Character Class[\d-]

\da digit

-the literal - (45₁₀ / 55₈ / 2D₁₆)

\d{5}a digit, repeated exactly 5 times

Non-Capturing Group(?:[\r\n])

Character Class[\r\n]

\ra carriage return (ASCII 13)

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

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

^\d{5}(?![\d-])|^\d{5}(?:-\d{4})(?!\d)|(?<!\d)\d{5}(?:-\d{4})(?:[\r\n])|(?<![\d-])\d{5}(?:[\r\n])

New

Nothing to match in the middle 06000 or 06000-0000 on this line

06111 these are ok 06222-1111

06333-1111 and these 06444

06555-333 these are not 06666-444

06777-66666 also not 06888-77777

06888-00001 but this last one is

06999-9999

this should not match 123456-1234

While this one should likely match:

12345

Regular Expression

Extraction