Regular Expressions 101

^start of line

Positive Lookahead(?=.{8}$)

.{8}any character (except for line terminators), repeated exactly 8 times

$end of line

Negative Lookahead(?![\d-]+$|[a-z-]+$)

1st Alternative[\d-]+$

Character Class[\d-]+

+matches at least one character from the set below:

\da digit

-the literal - (45₁₀ / 55₈ / 2D₁₆)

$end of line

2nd Alternative[a-z-]+$

Character Class[a-z-]+

+matches at least one character from the set below:

a-zone character from a (97₁₀) to z (122₁₀) (case sensitive)

-the literal - (45₁₀ / 55₈ / 2D₁₆)

$end of line

Negated Character Class[^\W_]+

+matches at least one character outside the set below:

\Wany non-word character

_the literal _ (95₁₀ / 137₈ / 5F₁₆)

Non-Capturing Group(?:-[^\W_]+)+

+repeats the group contents below at least once:

-the literal - (45₁₀ / 55₈ / 2D₁₆)

Negated Character Class[^\W_]+

+matches at least one character outside the set below:

\Wany non-word character

_the literal _ (95₁₀ / 137₈ / 5F₁₆)

$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.

Search reference

Regular Expression

^(?=.{8}$)(?![\d-]+$|[a-z-]+$)[^\W_]+(?:-[^\W_]+)+$

New

aa-99-99
99-23-bd
02-xx-04
ab-99-cz
sc-xd-49
99-xav-4
48-xyz-09
11-11-11
9-abc-01
xs-899-x
sss-99-x