Regular Expressions 101

Explanation

Pro

^start of line

Group 1([A-Za-z0-9]+([@_\-\.][A-Za-z0-9]*)?){6,15}

{6,15}repeats the group contents below between 6 and 15 times:

Character Class[A-Za-z0-9]+

+matches at least one character from the set below:

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

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

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

Group 2([@_\-\.][A-Za-z0-9]*)?

?repeats the group contents below at most once:

Character Class[@_\-\.]

@the literal @ (64₁₀ / 100₈ / 40₁₆)

_the literal _ (95₁₀ / 137₈ / 5F₁₆)

\-the literal - (45₁₀ / 55₈ / 2D₁₆)

\.the literal . (46₁₀ / 56₈ / 2E₁₆)

Character Class[A-Za-z0-9]*

*matches any number of characters from the set below:

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

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

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

$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

Detailed match information will be displayed here automatically.

27 tokens

^([A-Za-z0-9]+([@_\-\.][A-Za-z0-9]*)?){6,15}$

New

# Valid Input
user@site
asdasd_asdasdasd
Asdase-teqweqwe
asdasd.q234awdawd
# Invalid Inputs
user@@site
@usersite

# Valid Input
user@site
asdasd_asdasdasd
Asdase-teqweqwe
asdasd.q234awdawd
# Invalid Inputs
user@@site
@usersite