Phil Parker 
Tweet
2 December 2011
Postcode Regex
I was looking for a relatively simple postcode regex and came across this.
I removed a few of the capture groups (just retaining one for the outcode which left me with this little beauty:
^[Gg][Ii][Rr] 0[Aa]{2}|([A-Za-z][0-9]{1,2}|[A-Za-z][A-Ha-hJ-Yj-y][0-9]{1,2}|[A-Za-z][0-9][A-Za-z]|[A-Za-z][A-Ha-hJ-Yj-y][0-9]?[A-Za-z]) {0,1}[0-9][A-Za-z]{2}$
You can see a groovy script using this here:
http://groovyconsole.appspot.com/script/599002
def pattern = /^[Gg][Ii][Rr] 0[Aa]{2}|([A-Za-z][0-9]{1,2}|[A-Za-z][A-Ha-hJ-Yj-y][0-9]{1,2}|[A-Za-z][0-9][A-Za-z]|[A-Za-z][A-Ha-hJ-Yj-y][0-9]?[A-Za-z]) {0,1}[0-9][A-Za-z]{2}$/
assert !("SW1A 1AAA" =~ pattern).matches()
assert ("SW1A1AA" =~ pattern).matches()
assert ("SW1A 1AA" =~ pattern).matches()
assert ("SW1A 1AA" =~ pattern)[0][0] == "SW1A 1AA"
assert ("SW1A 1AA" =~ pattern)[0][1] == "SW1A"