Array::Array::IntSpan

Array::IntSpan(3)     User Contributed Perl Documentation    Array::IntSpan(3)



NAME
       Array::IntSpan - a Module for handling arrays using IntSpan techniques

SYNOPSIS
         use Array::IntSpan;

         my $foo = Array::IntSpan->new([0, 59, 'F'], [60, 69, 'D'], [80, 89, 'B']);

         print "A score of 84% results in a ".$foo->lookup(84).".\n";
         unless (defined($foo->lookup(70))) {
           print "The grade for the score 70% is currently undefined.\n";
         }

         $foo->set_range(70, 79, 'C');
         print "A score of 75% now results in a ".$foo->lookup(75).".\n";

         $foo->set_range(0, 59, undef);
         unless (defined($foo->lookup(40))) {
           print "The grade for the score 40% is now undefined.\n";
         }

         $foo->set_range(87, 89, 'B+');
         $foo->set_range(85, 100, 'A');
         $foo->set_range(100, 1_000_000, 'A+');


DESCRIPTION
       Array::IntSpan brings the speed advantages of Set::IntSpan (written by
       Steven McDougall) to arrays.  Uses include manipulating grades, routing
       tables, or any other situation where you have mutually exclusive ranges
       of integers that map to given values.

       Array::IntSpan::IP is also provided with the distribution.  It lets you
       use IP addresses in any of three forms (dotted decimal, network string,
       and integer) for the indices into the array.  See the POD for that
       module for more information.

       Installation instructions

       Standard Make::Maker approach or just copy Array/IntSpan.pm into
       site/lib/Array/IntSpan.pm and Array/IntSpan/IP.pm into
       site/lib/Array/IntSpan/IP.pm.

METHODS
       new

       The new method takes an optional list of array elements.  The elements
       should be in the form [start_index, end_index, value].  They should be
       in sorted order and there should be no overlaps.  The internal method
       _check_structure will be called to verify the data is correct.  If you
       wish to avoid the performance penalties of checking the structure, you
       can use Data::Dumper to dump an object and use that code to
       reconstitute it.

       set_range

       This method takes three parameters - the start_index, the end_index,
       and the value.  If you wish to erase a range, specify undef for the
       value.  It properly deals with overlapping ranges and will replace
       existing data as appropriate.  If the new range lies after the last
       existing range, the method will execute in O(1) time.  If the new range
       lies within the existing ranges, the method executes in O(n) time,
       where n is the number of ranges.  The code is not completely optimized
       and will make up to three calls to splice if the new range intersects
       with existing ranges.  It does not consolidate contiguous ranges that
       have the same value.

       If you have a large number of inserts to do, it would be beneficial to
       sort them first.  Sorting is O(n lg(n)), and since appending is O(1),
       that will be considerably faster than the O(n^2) time for inserting n
       unsorted elements.

       The method returns 0 if there were no overlapping ranges and 1 if there
       were.

       lookup

       This method takes as a single parameter the index to look up.  If there
       is an appropriate range, the method will return the associated value.
       Otherwise, it returns undef.

AUTHOR
       Toby Everett, teverett@alascom.att.com














3rd Berkeley Distribution    perl 5.005, patch 03            Array::IntSpan(3)