Regular Expressions 101

Pro

^start of line

Non-Capturing Group(?:_*[A-Za-z0-9]_*){4,}

{4,}repeats the group contents below at least 4 times:

_*the literal _ (95₁₀ / 137₈ / 5F₁₆) , repeated any number of times

Character Class[A-Za-z0-9]

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)

_*the literal _ (95₁₀ / 137₈ / 5F₁₆) , repeated any number of times

$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-z0-9]_*){4,}$

hello99____
abcd
_a_b_c_d
_a_b_c_d_
_a_b_c_d_e
____abcd
abcd____

___h8
bcd____
____a

hello99____
abcd
_a_b_c_d
_a_b_c_d_
_a_b_c_d_e
____abcd
abcd____

___h8
bcd____
____a