NAME
Geo::UK::Postcode::Regex - regular expressions for handling British postcodes
SYNOPSIS
See Geo::UK::Postcode::Regex::Simple for an alternative interface.
use Geo::UK::Postcode::Regex;
## REGULAR EXPRESSIONS
my $lax_re = Geo::UK::Postcode::Regex->regex;
my $strict_re = Geo::UK::Postcode::Regex->regex_strict;
my $valid_re = Geo::UK::Postcode::Regex->valid_regex;
# matching only
if ( $foo =~ $lax_re ) {...}
if ( $foo =~ $strict_re ) {...}
if ( $foo =~ $valid_re ) {...}
# matching and using components - see also parse()
if ( $foo =~ $lax_re ) {
my ( $area, $district, $sector, $unit ) = ( $1, $2, $3, $4 );
my $subdistrict = $district =~ s/([A-Z])$// ? $1 : undef;
...
}
if ( $foo =~ $strict_re ) {
my ( $area, $district, $sector, $unit ) = ( $1, $2, $3, $4 );
my $subdistrict = $district =~ s/([A-Z])$// ? $1 : undef;
...
}
if ( $foo =~ $valid_re ) {
my ( $outcode, $sector, $unit ) = ( $1, $2, $3 );
...
}
## VALIDATION METHODS
use Geo::UK::Postcode::Regex qw/ is_valid_pc is_strict_pc is_lax_pc /;
if (is_valid_pc("GE0 1UK")) {
...
}
if (is_strict_pc("GE0 1UK")) {
...
}
if (is_lax_pc("GE0 1UK")) {
...
}
## PARSING
my $parsed = Geo::UK::Postcode::Regex->parse("WC1H 9EB");
# returns:
# { area => 'WC',
# district => '1',
# subdistrict => 'H',
# sector => '9',
# unit => 'EB',
# outcode => 'WC1H',
# incode => '9EB',
# valid => 1,
# strict => 1,
# partial => 0,
# non_geographical => 0,
# bfpo => 0,
# }
# strict parsing (only valid characters):
...->parse( $pc, { strict => 1 } )
# valid outcodes only
...->parse( $pc, { valid => 1 } )
# match partial postcodes, e.g. 'WC1H', 'WC1H 9' - see below
...->parse( $pc, { partial => 1 } )
## PARSING PARTIAL POSTCODES
# outcode (district) only
my $parsed = Geo::UK::Postcode::Regex->parse( "AB10", { partial => 1 } );
# returns:
# { area => 'AB',
# district => '10',
# subdistrict => undef,
# sector => undef,
# unit => undef,
# outcode => 'AB10',
# incode => undef,
# valid => 1,
# strict => 1,
# partial => 1,
# non_geographical => 0,
# bfpo => 0,
# }
# sector only
my $parsed = Geo::UK::Postcode::Regex->parse( "AB10 1", { partial => 1 } );
# returns:
# { area => 'AB',
# district => '10',
# subdistrict => undef,
# sector => 1,
# unit => undef,
# outcode => 'AB10',
# incode => '1',
# valid => 1,
# strict => 1,
# partial => 1,
# non_geographical => 0,
# bfpo => 0,
# }
## EXTRACT OUTCODE FROM POSTCODE
my $outcode = Geo::UK::Postcode::Regex->outcode("AB101AA"); # returns 'AB10'
my $outcode = Geo::UK::Postcode::Regex->outcode( $postcode, { valid => 1 } )
or die "Invalid postcode";
## EXTRACT POSTCODES FROM TEXT
# \%options as per parse, excluding partial
my @extracted = Geo::UK::Postcode::Regex->extract( $text, \%options );
## POSTTOWNS
my @posttowns = Geo::UK::Postcode::Regex->outcode_to_posttowns($outcode);
## OUTCODES
my @outcodes = Geo::UK::Postcode::Regex->posttown_to_outcodes($posttown);DESCRIPTION
Parsing UK postcodes with regular expressions. This package has been separated from Geo::UK::Postcode so it can be installed and used with fewer dependencies.
Can handle partial postcodes (just the outcode or sector) and can test against valid characters and currently valid outcodes.
Also can determine the posttown(s) from a postcode.
Districts and post town information taken from: https://en.wikipedia.org/wiki/Postcode_districts
NOTES AND LIMITATIONS
When parsing a partial postcode, whitespace may be required to separate the outcode from the sector.
For example the sector 'B1 1' cannot be distinguished from the district 'B11' without whitespace. This is not a problem when parsing full postcodes.
VALIDATION METHODS
The following methods are for validating postcodes to various degrees.
Geo::UK::Postcode::Regex::Simple may provide a more convenient way of using and customising these.
regex, strict_regex, valid_regex
Return regular expressions to parse postcodes and capture the constituent parts: area, district, sector and unit (or outcode, sector and unit in the case of valid_regex).
strict_regex checks that the postcode only contains valid characters according to the postcode specifications.
valid_regex checks that the outcode currently exists.
regex_partial, strict_regex_partial, valid_regex_partial
As above, but matches on partial postcodes of just the outcode or sector
is_valid_pc, is_strict_pc, is_lax_pc
if (is_valid_pc( "AB1 2CD" ) ) { ... }Alternative way to access the regexes.
PARSING METHODS
The following methods are for parsing postcodes or strings containing postcodes.
PARSING_OPTIONS
The parsing methods can take the following options, passed via a hashref:
- strict
-
Postcodes must not contain invalid characters according to the postcode specification. For example a 'Q' may not appear as the first character.
- valid
-
Postcodes must contain an outcode (area + district) that currently exists, in addition to conforming to the
strictdefinition.Returns false if string is not a currently existing outcode.
- partial
-
Allows partial postcodes to be matched. In practice this means either an outcode ( area and district ) or an outcode together with the sector.
extract
my @extracted = Geo::UK::Postcode::Regex->extract( $string, \%options );Returns a list of full postcodes extracted from a string.
parse
my $parsed = Geo::UK::Postcode::Regex->parse( $pc, \%options );Returns hashref of the constituent parts - see SYNOPSIS. Missing parts will be set as undefined.
outcode
my $outcode = Geo::UK::Postcode::Regex->outcode( $pc, \%options );Extract the outcode (area and district) from a postcode string. Will work on full or partial postcodes.
LOOKUP METHODS
outcode_to_posttowns
my ( $posttown1, $posttown2, ... )
= Geo::UK::Postcode::Regex->outcode_to_posttowns($outcode);Returns posttown(s) for supplied outcode.
Note - most outcodes will only have one posttown, but some are shared between two posttowns.
posttown_to_outcodes
my @outcodes = Geo::UK::Postcode::Regex->posttown_to_outcodes($posttown);Returns the outcodes covered by a posttown. Note some outcodes are shared between posttowns.
outcodes_lookup
my %outcodes = %{ Geo::UK::Postcode::Regex->outcodes_lookup };
print "valid outcode" if $outcodes{$outcode};
my @posttowns = @{ $outcodes{$outcode} };Hashref of outcodes to posttown(s);
posttowns_lookup
my %posttowns = %{ Geo::UK::Postcode::Regex->posttowns_lookup };
print "valid posttown" if $posttowns{$posttown};
my @outcodes = @{ $[posttowns{$posttown} };Hashref of posttown to outcode(s);
SEE ALSO
AUTHOR
Michael Jemmeson <mjemmeson@cpan.org>
COPYRIGHT
Copyright 2014- Michael Jemmeson
LICENSE
This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself.