Regular Expressions 101

Explanation

Pro

^start of line

Character Class[a-zA-Z]

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

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

Non-Capturing Group(?:_*[a-zA-Z]){4,9}

{4,9}repeats the group contents below between 4 and 9 times:

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

Character Class[a-zA-Z]

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

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

$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](?:_*[a-zA-Z]){4,9}$

New

Valid values:

a_b_c_d_e

a_b_c_________________d_e

abcde

aa_bcd

Non Valid values:

_abcde

adebc_

a_________________________b

Valid values:

a_b_c_d_e

a_b_c_________________d_e

abcde

aa_bcd

Non Valid values:

_abcde

adebc_

a_________________________b