Regular Expressions 101

Pro

^start of line

Negative Lookahead(?!.* )

.*any character (except for line terminators), repeated any number of times

the literal text

Negative Lookahead(?!.*[-,/.]{2})

.*any character (except for line terminators), repeated any number of times

Character Class[-,/.]{2}

{2}matches exactly 2 characters from the set below:

-the literal - (45₁₀ / 55₈ / 2D₁₆)

,the literal , (44₁₀ / 54₈ / 2C₁₆)

/the literal / (47₁₀ / 57₈ / 2F₁₆)

.the literal . (46₁₀ / 56₈ / 2E₁₆)

Negative Lookahead(?!.*(?:[^\d\n]*\d){6})

.*any character (except for line terminators), repeated any number of times

Non-Capturing Group(?:[^\d\n]*\d){6}

{6}repeats the group contents below exactly 6 times:

Negated Character Class[^\d\n]*

*matches any number of characters outside the set below:

\da digit

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

\da digit

Negative Lookahead(?!.*([a-zA-Z])\1\1)

.*any character (except for line terminators), repeated any number of times

Group 1([a-zA-Z])

Character Class[a-zA-Z]

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

A-Zone character from A (65₁₀) to Z (90₁₀) (case sensitive)

\1the text saved by group 1

.{3,50}any character (except for line terminators), repeated between 3 and 50 times

$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

No unit tests · Add a test to get started

25 tokens

^(?!.*  )(?!.*[-,/.]{2})(?!.*(?:[^\d\n]*\d){6})(?!.*([a-zA-Z])\1\1).{3,50}$

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