Regular Expressions 101

Pro

Non-Capturing Group(?:\s|^)

1st Alternative\s

\sany whitespace character

2nd Alternative^

^start of line

Negative Lookahead(?!(?:elem|asdf)?-)

Non-Capturing Group(?:elem|asdf)?

?repeats the group contents below at most once:

1st Alternativeelem

elemthe literal text elem (case sensitive)

2nd Alternativeasdf

asdfthe literal text asdf (case sensitive)

-the literal - (45₁₀ / 55₈ / 2D₁₆)

Group 1([\w-]+)

Character Class[\w-]+

+matches at least one character from the set below:

\wany word character

-the literal - (45₁₀ / 55₈ / 2D₁₆)

\ban ASCII word boundary

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

(?:\s|^)(?!(?:elem|asdf)?-)([\w-]+)\b

New

any-dashed-strings
this-can-be-matched-even-though-its-big
elem-this-cannot-be-
-
asdf-this-cannot-be-matched
-this-cannot-be-matched

any-dashed-strings
this-can-be-matched-even-though-its-big
elem-this-cannot-be-
-
asdf-this-cannot-be-matched
-this-cannot-be-matched