Geo::UK::Postcode::Regex(3p)

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->strict_regex;
    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 (aka Regexp). 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>

IMPORTANT CHANGES FOR VERSION 0.014
Please note that various bugfixes have changed the following:

•   Unanchored regular expressions no longer match valid postcodes within invalid ones.

•   Unanchored regular expressions in partial mode now can match a valid or strict outcode with an invalid incode.

Please get in touch if you have any questions.

See Geo::UK::Postcode::Regex::Simple for other changes affecting the Simple interface.

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 "strict" definition.

    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

•   Geo::UK::Postcode - companion package, provides Postcode objects

•   Geo::Address::Mail::UK

•   Geo::Postcode

•   Data::Validation::Constraints::Postcode

•   CGI::Untaint::uk_postcode

•   Form::Validator::UKPostcode

SUPPORT

  Bugs / Feature Requests
Please report any bugs or feature requests through the issue tracker at <https://github.com/mjemmeson/geo-uk-postcode-regex/issues>. You will be notified automatically of any progress on your issue.

  Source Code
This is open source software. The code repository is available for public review and contribution under the terms of the license.

<https://github.com/mjemmeson/geo-uk-postcode-regex>

    git clone git://github.com/mjemmeson/geo-uk-postcode-regex.git

AUTHOR
Michael Jemmeson <mjemmeson@cpan.org>

CONTRIBUTORS

•   Tom Bloor "TBSLIVER"

COPYRIGHT
Copyright 2015-2017 Michael Jemmeson

LICENSE
This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself.