Regular Expressions 101

^start of line

Group 1([A-Z]{1,2}\d[A-Z\d]? ?\d[A-Z]{2}|GIR ?0A{2})

1st Alternative[A-Z]{1,2}\d[A-Z\d]? ?\d[A-Z]{2}

Character Class[A-Z]{1,2}

{1,2}matches between 1 and 2 characters from the set below:

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

\da digit

Character Class[A-Z\d]?

?matches at most one character from the set below:

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

\da digit

?optionally matches the literal (32₁₀ / 40₈ / 20₁₆)

\da digit

Character Class[A-Z]{2}

{2}matches exactly 2 characters from the set below:

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

2nd AlternativeGIR ?0A{2}

GIRthe literal text GIR (case insensitive)

?optionally matches the literal (32₁₀ / 40₈ / 20₁₆)

0the literal 0 (48₁₀ / 60₈ / 30₁₆)

A{2}the literal A (65₁₀ / 101₈ / 41₁₆) (case insensitive), repeated exactly 2 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

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

Detailed match information will be displayed here automatically.

Search reference

Regular Expression

^([A-Z]{1,2}\d[A-Z\d]? ?\d[A-Z]{2}|GIR ?0A{2})$

Test String
New

A1A 1AA
A1 1AA
A11 1AA
AA1 1AA
AA1A 1AA
AA11 1AA
A1A1AA
A11AA
A111AA
AA11AA
AA1A1AA
AA111AA
GIR 0AA
GIR0AA
a1a 1aa
a1 1aa
a11 1aa
aa1 1aa
aa1a 1aa
aa11 1aa
a1a1aa
a11aa
a111aa
aa11aa
aa1a1aa
aa111aa
gir 0aa
gir0aa

Regular Expression

Test StringNew

SubstitutionProcessing...

Test String
New

Substitution
Processing...