David J. Oswald > Math-Pandigital-0.04 > Math::Pandigital

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Module Version: 0.04   Source  

NAME ^

Math::Pandigital - Pandigital number detection.

SYNOPSIS ^

    use Math::Pandigital;

    my $p = Math::Pandigital->new;
    my $test = '1234567890';
    if( $p->is_pandigital( $test ) ) {
      print "$test is pandigital.\n";
    }
    else {
      print "$test is not pandigital.\n";
    }


    my $p = Math::Pandigital->new( base => 8, zeroless => 1, unique => 1 );

    print "012345567 is pandigital\n" if $p->is_pandigital('012345567'); # No.
    print "1234567 is pandigital\n" if $p->is_pandigital('1234567');     # Yes.

DESCRIPTION ^

A Pandigital number is an integer that contains at least one of each digit in its base system. For example, a base-2 pandigital number must contain both 0 and 1. A base-10 pandigital number must contain 0, 1, 2, 3, 4, 5, 6, 7, 8, and 9. This module can detect pandigital numbers in base 1 through base 10, as well as hexidecimal.

Pandigital numbers usually include zero. However, zeroless pandigital numbers, containing (in base-10), 1 .. 9, and not 0 are sometimes permitted. This module can accommodate that need.

Additionally, some uses of pandigital numbers require that there be no repeated digits. In such a case, the base-2 number 10 would be pandigital, whereas 101 would not. Again, this module accommodates that possibility.

Math::Pandigital provides a class that can be instantiated in any base, from 1 through 10, or 16 (hex), and can be used to detect pandigital numbers. It may also be configured to accept repeated digits, or to reject them, and to require the 'zero' digit, or to reject it.

EXPORTS ^

No exports.

SUBROUTINES AND METHODS ^

new

    my $p = Math::Pandigital->new;

Constructs a Math::Pandigital test object. If no parameters are passed, the tests will assume base ten, requiring a "zero", and permitting repeated digits.

Optional constructor parameters

Any (or all) of the following parameters may optionally be used to configure the test object.

base

    my $p = Math::Pandigital->new( base => 16 );

Set's the base to any value from 1 to 10, or 16. If the goal is to detect pandigitality of a binary number, select base => 2, for example. If not specified, the default is base ten. Common options are 2 (binary), 8 (octal), 10 (decimal), and 16 (hex). Base 1 is permitted (unary), as is any value between one and ten, inclusive.

For base-16 tests, the digits A..F will be treated case-insensitively.

Unary (base 1) pandigital numbers are zeroless; the only reasonable digit is '1'. Therefore, when setting base => 1, one must also set zeroless => 1.

unique

    my $p = Math::Pandigital->new( unique => 1 );

A Boolean flag used to set whether or not the pandigital number may contain repeated digits. For example, in base 2, with unique set, there are only two pandigital numbers: 01, and 10. With unique unset (the default), any binary number of any length is permitted so long as it has at least one zero, and one one. The default is the traditional definition of a pandigital number: repeated digits allowed.

zeroless

    my $p = Math::Pandigital->new( zeroless => 1 );

A Boolean flag. The default is false (zeros required). When unset (or the default accepted), the pandigital number must include a zero. When set to true, the pandigital number may not include a zero.

When a base 1 is selected (unary), it's required to explicitly set zeroless to true; the only reasonable digit is '1'.

A brief example:

    my $p = Math::Pandigital->new( base => 4, zeroless => 1, unique => 1 );

The preceeding instantiation would set up a test that allows the following numbers to match: 123, 231, 213, 321, 312, and 132. It would reject any number with a zero, or more (or less) than three digits.

is_pandigital

    $p->is_pandigital($n);

$n may be any string. If the string contains only numeric digits that match the criteria set forth when the test object is constructed, true is returned. If the string contains any digits that aren't part of the base, or if it fails to contain all necessary digits, or if it violates the uniqueness setting (if set), it will return false. The letters 'A' through 'F' (case insensitive) are considered numeric digits when operating in base 16 (hex) mode, and in base 1 (unary), the numeral 1 is the only possible digit.

In keeping with the definition for pandigital numbers, leading zeros are not significant, and will be stripped before testing. Thus, '0123456789' is not zerofull pandigital in base ten, because it is considered as '123456789'.

Pass hexidecimal numbers as a string of hex digits, not as their native 0xNNNNNNNNNNNNNNNN representations. This is for two reasons. First, a 16-digit hex number corresponds to 1.84467440737E+19, which is large enough that the internal representation will lose significant digits if stored and passed numerically. Second, within Math::Pandigital the string of digits is treated just as that, a string of digits.

Setting a base of 1 (unary), and a zeroless of false (zeros included, or zeroful) will cause the constructor to throw an exception; the only permissible digit in a unary pandigital is '1'. If this seems counterintuitive, remember that leading zeros are stripped, so it wouldn't make sense for unary pandigitals to use '0' as the marker digit. This being the case, zeroless base-2 (binary) pandigitals, and base-1 (unary) pandigitals, which must always be zeroless are practically the same thing, though conceptually they differ.

CAVEATS & WARNINGS ^

While any length of string of digits is permitted, there is no silver bullet; the computational complexity of the is_pandigital() test is linear in the worst case. However, where profiling for the general case has shown them to be beneficial, optimizations have been used to reject non-pandigitals as quickly as practical.

Math::Pandigital's test suite currently has 100% coverage.

CONFIGURATION AND ENVIRONMENT ^

No special considerations.

DEPENDENCIES ^

Perl 5.6.2, Moo, and MooX::Types::MooseLike are required.

INCOMPATIBILITIES ^

No known incompatibilities.

SEE ALSO ^

http://en.wikipedia.org/wiki/Pandigital_number

AUTHOR ^

David Oswald <davido at cpan dot org>

DIAGNOSTICS ^

SUPPORT ^

You can find documentation for this module with the perldoc command.

    perldoc Math::Pandigital

This module is maintained in a public repo at Github. You may look for information at:

ACKNOWLEDGEMENTS ^

LICENSE AND COPYRIGHT ^

Copyright 2012 David Oswald.

This program is free software; you can redistribute it and/or modify it under the terms of either: the GNU General Public License as published by the Free Software Foundation; or the Artistic License.

See http://dev.perl.org/licenses/ for more information.

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