regular-expressions.md

Start of string

^

0 or more

+

1 or more

*

0 or 1

?

Any char but \n

.

Exactly 3

{3}

3 or more

{3,}

3 or 4 or 5

{3,5}

3 or 5

{3|5}

3 or 4 or 5

[345]

Not 3 or 4

[^34]

Lowercase a-z

[a-z]

Uppercase A-Z

[A-Z]

Digit 0-9

[0-9]

Digit

\d

Not digit

\D

A-Z,a-z,0-9

\w

Not A-Z,a-z,0-9

\W

White space (\t\r\n\f)

\s

Not (\t\r\n\f)

\S

"rege" or "regx"

reg[ex]

''rege'' or ''regex''

regex?

''rege'' w/ 0 or more x

regex*

''rege'' w/ 1 or more x

regex+

''Regex'' or ''regex''

[Rr]egex

Exactly 3 digits

\d{3}

3 or more digits

\d{3,)

Any vowel

[aeiou]

Numbers 03-25

(0[3-9] | 1[0-9] | 2[0-5])