Regular Expressions 101

Pro

Positive Lookbehind(?<=\s|^)

1st Alternative\s

\sany whitespace character

2nd Alternative^

^start of string

#the literal # (35₁₀ / 43₈ / 23₁₆)

Group 1([^\d_\s\W][\p{L}\d]{2,})

Negated Character Class[^\d_\s\W]

\da digit

_the literal _ (95₁₀ / 137₈ / 5F₁₆)

\sany whitespace character

\Wany non-word character

Character Class[\p{L}\d]{2,}

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

\p{L}any Unicode letter

\da digit

Global pattern flags

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

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25 tokens

Regular Expression

(?<=\s|^)#([^\d_\s\W][\p{L}\d]{2,})

Unit Tests

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