Regular Expressions 101

Explanation

Pro

Positive Lookahead(?=[@]){1}

{1}repeats the group contents below exactly 1 time:

Character Class[@]

@the literal @ (64₁₀ / 100₈ / 40₁₆)

Character Class[a-zA-Z@]+

+matches at least one character from the set below:

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

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

@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

(?=[@]){1}[a-zA-Z@]+$

New

abcd@.
@ab.cd

a@cd@.
abcd@
abcd@snfkeksjfjr@@@@@@

abcd@.
@ab.cd

a@cd@.
abcd@
abcd@snfkeksjfjr@@@@@@