Regular Expressions 101

Pro

^start of string

Positive Lookahead(?=.{0,50}$)

.{0,50}any character (except for line terminators), repeated between 0 and 50 times

$end of string

^start of string

Group 1((https?:\/\/)?(www\.)?)?

?repeats the group contents below at most once:

Group 2(https?:\/\/)?

?repeats the group contents below at most once:

httpthe literal text http (case sensitive)

s?optionally matches the literal s (115₁₀ / 163₈ / 73₁₆) (case sensitive)

:the literal : (58₁₀ / 72₈ / 3A₁₆)

\/the literal / (47₁₀ / 57₈ / 2F₁₆)

Group 3(www\.)?

?repeats the group contents below at most once:

wwwthe literal text www (case sensitive)

\.the literal . (46₁₀ / 56₈ / 2E₁₆)

Group 4([a-zA-Z0-9&\-\'\+\$%_,\/;#])+

+repeats the group contents below at least once:

Character Class[a-zA-Z0-9&\-\'\+\$%_,\/;#]

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

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

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

&the literal & (38₁₀ / 46₈ / 26₁₆)

athe literal a (97₁₀ / 141₈ / 61₁₆) (case sensitive)

mthe literal m (109₁₀ / 155₈ / 6D₁₆) (case sensitive)

pthe literal p (112₁₀ / 160₈ / 70₁₆) (case sensitive)

;the literal ; (59₁₀ / 73₈ / 3B₁₆)

\-the literal - (45₁₀ / 55₈ / 2D₁₆)

\'the literal ' (39₁₀ / 47₈ / 27₁₆)

\+the literal + (43₁₀ / 53₈ / 2B₁₆)

\$the literal $ (36₁₀ / 44₈ / 24₁₆)

%the literal % (37₁₀ / 45₈ / 25₁₆)

_the literal _ (95₁₀ / 137₈ / 5F₁₆)

,the literal , (44₁₀ / 54₈ / 2C₁₆)

\/the literal / (47₁₀ / 57₈ / 2F₁₆)

;the literal ; (59₁₀ / 73₈ / 3B₁₆)

#the literal # (35₁₀ / 43₈ / 23₁₆)

\.the literal . (46₁₀ / 56₈ / 2E₁₆)

Group 5([a-z]){2,4}

{2,4}repeats the group contents below between 2 and 4 times:

Character Class[a-z]

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

$end of string

Detailed match information will be displayed here automatically.

26 tokens

Regular Expression

^(?=.{0,50}$)^((https?:\/\/)?(www\.)?)?([a-zA-Z0-9&amp;\-\'\+\$%_,\/;#])+\.([a-z]){2,4}$

New

www.com