Regular Expressions 101

Pro

^start of line

Non-Capturing Group(?:([\p{Lu}0-9_]{2,})|(\p{Lu}[\p{L}0-9_$]+)|([\p{L}_$][\p{L}0-9_$]*))

1st Alternative([\p{Lu}0-9_]{2,})

Group 1([\p{Lu}0-9_]{2,})

Character Class[\p{Lu}0-9_]{2,}

{2,}matches at least 2 characters from the set below:

\p{Lu}an uppercase letter

0-9one character from 0 (48₁₀) to 9 (57₁₀)

_the literal _ (95₁₀ / 137₈ / 5F₁₆)

2nd Alternative(\p{Lu}[\p{L}0-9_$]+)

Group 2(\p{Lu}[\p{L}0-9_$]+)

\p{Lu}an uppercase letter

Character Class[\p{L}0-9_$]+

+matches at least one character from the set below:

\p{L}any Unicode letter

0-9one character from 0 (48₁₀) to 9 (57₁₀)

_the literal _ (95₁₀ / 137₈ / 5F₁₆)

$the literal $ (36₁₀ / 44₈ / 24₁₆)

3rd Alternative([\p{L}_$][\p{L}0-9_$]*)

Group 3([\p{L}_$][\p{L}0-9_$]*)

Character Class[\p{L}_$]

\p{L}any Unicode letter

_the literal _ (95₁₀ / 137₈ / 5F₁₆)

$the literal $ (36₁₀ / 44₈ / 24₁₆)

Character Class[\p{L}0-9_$]*

*matches any number of characters from the set below:

\p{L}any Unicode letter

0-9one character from 0 (48₁₀) to 9 (57₁₀)

_the literal _ (95₁₀ / 137₈ / 5F₁₆)

$the literal $ (36₁₀ / 44₈ / 24₁₆)

\ban ASCII word boundary

Global pattern flags

m modifier: multiline. Causes ^ and $ to match the start and end of each line, not only the start and end of the string

g modifier: global. Finds all matches instead of stopping after the first

Ready to run

25 tokens

^(?:([\p{Lu}0-9_]{2,})|(\p{Lu}[\p{L}0-9_$]+)|([\p{L}_$][\p{L}0-9_$]*))\b