Regular Expressions 101

Explanation
Pro

^start of line

Character Class[a-z]

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

Character Class[a-z0-9_\.]{5,32}

{5,32}matches between 5 and 32 characters from the set below:

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

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

_the literal _ (95₁₀ / 137₈ / 5F₁₆)

\.the literal . (46₁₀ / 56₈ / 2E₁₆)

@the literal @ (64₁₀ / 100₈ / 40₁₆)

Character Class[a-z0-9]{2,}

{2,}matches at least 2 characters from the set below:

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

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

Group 1(\.[a-z0-9]{2,4}){1,2}

{1,2}repeats the group contents below between 1 and 2 times:

\.the literal . (46₁₀ / 56₈ / 2E₁₆)

Character Class[a-z0-9]{2,4}

{2,4}matches between 2 and 4 characters from the set below:

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

m modifier: multiline. Causes ^ and $ to match the start and end of each line, not only the start and end of the string

g modifier: global. Finds all matches instead of stopping after the first

Detailed match information will be displayed here automatically.

25 tokens

^[a-z][a-z0-9_\.]{5,32}@[a-z0-9]{2,}(\.[a-z0-9]{2,4}){1,2}$

New

khoapd7@fpt.com.vn
new_email@example.com
khoadeptrai_thanhlich_vodich_khapvutru@gmail.com
foo@example.com

khoapd7@fpt.com.vn
new_email@example.com
khoadeptrai_thanhlich_vodich_khapvutru@gmail.com
foo@example.com