Regular Expressions 101

Explanation

Pro

^start of line

Negative Lookahead(?!.*@.*@)

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

@the literal @ (64₁₀ / 100₈ / 40₁₆)

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

@the literal @ (64₁₀ / 100₈ / 40₁₆)

Character Class[A-Za-z\d@]+

+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)

\da digit

@the literal @ (64₁₀ / 100₈ / 40₁₆)

$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.

25 tokens

^(?!.*@.*@)[A-Za-z\d@]+$

New

Ab01@
Ab0@1
@Ab01
@Ab01
Ab@01