regex101: UK postcodes

^start of line

Group 1((gir *0aa)|((((?![qvx])[a-z][a-hk-y]?[0-9][0-9]?)|(((?![qvx])[a-z][0-9][a-hjkstuw])|((?![qvx])[a-z][a-hk-y][0-9][abehmnprvwxy]))) *([0-9](?![cikmov])[a-z]{2}))|(((?![qvx])[a-z][a-hk-y]?[0-9][0-9]?)|((?![qvx])[a-z][0-9][a-hjkstuw])|((?![qvx])[a-z][a-hk-y][0-9][abehmnprvwxy])))

1st Alternative(gir *0aa)

Group 2(gir *0aa)

girthe literal text gir (case insensitive)

*the literal (32₁₀ / 40₈ / 20₁₆) , repeated any number of times

0aathe literal text 0aa (case insensitive)

2nd Alternative((((?![qvx])[a-z][a-hk-y]?[0-9][0-9]?)|(((?![qvx])[a-z][0-9][a-hjkstuw])|((?![qvx])[a-z][a-hk-y][0-9][abehmnprvwxy]))) *([0-9](?![cikmov])[a-z]{2}))

Group 3((((?![qvx])[a-z][a-hk-y]?[0-9][0-9]?)|(((?![qvx])[a-z][0-9][a-hjkstuw])|((?![qvx])[a-z][a-hk-y][0-9][abehmnprvwxy]))) *([0-9](?![cikmov])[a-z]{2}))

Group 4(((?![qvx])[a-z][a-hk-y]?[0-9][0-9]?)|(((?![qvx])[a-z][0-9][a-hjkstuw])|((?![qvx])[a-z][a-hk-y][0-9][abehmnprvwxy])))

1st Alternative((?![qvx])[a-z][a-hk-y]?[0-9][0-9]?)

Group 5((?![qvx])[a-z][a-hk-y]?[0-9][0-9]?)

Negative Lookahead(?![qvx])

Character Class[qvx]

qthe literal q (113₁₀ / 161₈ / 71₁₆) (case insensitive)

vthe literal v (118₁₀ / 166₈ / 76₁₆) (case insensitive)

xthe literal x (120₁₀ / 170₈ / 78₁₆) (case insensitive)

Character Class[a-z]

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

Character Class[a-hk-y]?

?matches at most one character from the set below:

a-hone character from a (97₁₀) to h (104₁₀) (case insensitive)

k-yone character from k (107₁₀) to y (121₁₀) (case insensitive)

Character Class[0-9]

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

Character Class[0-9]?

?matches at most one character from the set below:

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

2nd Alternative(((?![qvx])[a-z][0-9][a-hjkstuw])|((?![qvx])[a-z][a-hk-y][0-9][abehmnprvwxy]))

Group 6(((?![qvx])[a-z][0-9][a-hjkstuw])|((?![qvx])[a-z][a-hk-y][0-9][abehmnprvwxy]))

1st Alternative((?![qvx])[a-z][0-9][a-hjkstuw])

Group 7((?![qvx])[a-z][0-9][a-hjkstuw])

Negative Lookahead(?![qvx])

Character Class[qvx]

qthe literal q (113₁₀ / 161₈ / 71₁₆) (case insensitive)

vthe literal v (118₁₀ / 166₈ / 76₁₆) (case insensitive)

xthe literal x (120₁₀ / 170₈ / 78₁₆) (case insensitive)

Character Class[a-z]

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

Character Class[0-9]

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

Character Class[a-hjkstuw]

a-hone character from a (97₁₀) to h (104₁₀) (case insensitive)

jthe literal j (106₁₀ / 152₈ / 6A₁₆) (case insensitive)

kthe literal k (107₁₀ / 153₈ / 6B₁₆) (case insensitive)

sthe literal s (115₁₀ / 163₈ / 73₁₆) (case insensitive)

tthe literal t (116₁₀ / 164₈ / 74₁₆) (case insensitive)

uthe literal u (117₁₀ / 165₈ / 75₁₆) (case insensitive)

wthe literal w (119₁₀ / 167₈ / 77₁₆) (case insensitive)

2nd Alternative((?![qvx])[a-z][a-hk-y][0-9][abehmnprvwxy])

Group 8((?![qvx])[a-z][a-hk-y][0-9][abehmnprvwxy])

Negative Lookahead(?![qvx])

Character Class[a-z]

Character Class[a-hk-y]

Character Class[0-9]

Character Class[abehmnprvwxy]

*the literal (32₁₀ / 40₈ / 20₁₆) , repeated any number of times

Group 9([0-9](?![cikmov])[a-z]{2})

3rd Alternative(((?![qvx])[a-z][a-hk-y]?[0-9][0-9]?)|((?![qvx])[a-z][0-9][a-hjkstuw])|((?![qvx])[a-z][a-hk-y][0-9][abehmnprvwxy]))

$end of line

Global pattern flags

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

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

Search reference

Regular Expression

^((gir *0aa)|((((?![qvx])[a-z][a-hk-y]?[0-9][0-9]?)|(((?![qvx])[a-z][0-9][a-hjkstuw])|((?![qvx])[a-z][a-hk-y][0-9][abehmnprvwxy]))) *([0-9](?![cikmov])[a-z]{2}))|(((?![qvx])[a-z][a-hk-y]?[0-9][0-9]?)|((?![qvx])[a-z][0-9][a-hjkstuw])|((?![qvx])[a-z][a-hk-y][0-9][abehmnprvwxy])))$

New

GIR 0AA

W1 6LS
N1C 4UQ
N17 6LA
SW8 1UQ
CW3 9SS
SE5 0EG
WC2H 7LT
WC1N 2PL
HU12 0AR

N1C4UQ
N176LA
SW81UQ
CW39SS
SE50EG
WC2H7LT
WC1N2PL
HU120AR

W1
N1C
N17
SW8
CW3
SE5
WC2H
WC1N
HU12

QA12
AJ12
Q1A
A1V
QA1N
AZ1N
AB1Z

Regular Expressions 101

Regular Expression

Substitution