/ 
Geo-UK-Postcode-0.004
River stage zero No dependents
/ Geo::UK::Postcode::Regex

NAME

Geo::UK::Postcode::Regex - regular expressions for handling British postcodes

VERSION

version 0.004

SYNOPSIS

use Geo::UK::Postcode::Regex;

## REGULAR EXPRESSIONS

my $loose_re  = Geo::UK::Postcode::Regex->regex;
my $strict_re = Geo::UK::Postcode::Regex->regex_strict;
my $valid_re  = Geo::UK::Postcode::Regex->valid_regex;

if ( $foo =~ $loose_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 );
    ...
}


## 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_outcode    => 1 | 0,
#     strict           => 1 | 0,
#     partial          => 1 | 0,
#     non_geographical => 1 | 0,
#     bfpo             => 1 | 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'
...->parse( $pc, { partial => 1 } )


## EXTRACT OUTCODE
my $outcode = Geo::UK::Postcode::Regex->outcode("AB101AA"); # returns 'AB10'

my $outcode = Geo::UK::Postcode::Regex->outcode( $postcode, { valid => 1 } )
    or die "Invalid postcode";


## 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 can be used separately to avoid the overhead of loading any 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.

METHODS

strict_regex, 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.

strict_regex_partial, regex_partial, valid_regex_partial

As above, but matches on partial postcodes of just the outcode or sector

parse

my $parsed = Geo::UK::Postcode::Regex->parse( $pc, \%opts );

Returns hashref of the constituent parts.

Options:

strict

Returns false if string contains invalid characters (e.g. a Q as first letter)

valid

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 .

outcode

my $outcode = Geo::UK::Postcode::Regex->outcode( $pc, \%opts );

Extract the outcode (area and district) from a postcode string. Will work on full or partial postcodes.

Second argument is a hashref of options - see parse()

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::Postcodes::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::Postcodes::Regex->posttowns_lookup };
print "valid posttown" if $posttowns{$posttown};
my @outcodes = @{ $[posttowns{$posttown} };

Hashref of posttown to outcode(s);

AUTHOR

Michael Jemmeson <mjemmeson@cpan.org>

CONTRIBUTOR

Michael Jemmeson <michael.jemmeson@cpan.org>

COPYRIGHT AND LICENSE

This software is copyright (c) 2013 by Michael Jemmeson <mjemmeson@cpan.org>.

This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.