Regular Expressions 101

(?xi)applies the following effective flags to the remainder of the pattern: gmxi

x modifier: extended. Ignores unescaped whitespace and comments outside character classes

i modifier: insensitive. Matches without distinguishing uppercase and lowercase letters

^start of line

Group 1( (DE)?[0-9]{9}|)

1st Alternative (DE)?[0-9]{9}

Group 2(DE)?

?repeats the group contents below at most once:

DEthe literal text DE (case insensitive)

Character Class[0-9]{9}

{9}matches exactly 9 characters from the set below:

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

2nd Alternative — matches an empty string

$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.

Search reference

Regular Expression

(?xi)^( (DE)?[0-9]{9}|)$

New

ATU99999999
BE0999999999
BG999999999
HR12345678901
CY99999999L
CZ12345678
DK99999999
EE123456789
FI99999999
FRXX999999999
DE999999999
EL123456789
HU12345678
IE1S23456L
IE1234567T
IE1234567TW
IE1234567FA
ESA12345678
ESZ1234567E
DE813992525

Regular Expression

Extraction