The London Perl and Raku Workshop takes place on 26th Oct 2024. If your company depends on Perl, please consider sponsoring and/or attending.

# NAME

Number::RangeTracker - Keep track of numerical ranges quickly

Version 0.6.1

# SYNOPSIS

Create and modify ranges (three range syntaxes shown):

``````    my \$range = Number::RangeTracker->new;
\$range->add( [ 1, 10 ], '11..20' );
\$range->remove( 6, 15 );``````

Output ranges, their complement, or integers within ranges (differences between scalar and list contexts shown):

``````    \$range->output;
# Scalar context: '1..5,16..20'
# List context:   ( 1 => 5, 16 => 20 )

\$range->complement;
# Scalar context: '-inf..0,6..15,21..+inf'
# List context:   ( -inf => 0, 6 => 15, 21 => +inf )

\$range->integers;
# Scalar context: '1,2,3,4,5,16,17,18,19,20'
# List context:   ( 1, 2, 3, 4, 5, 16, 17, 18, 19, 20 )``````

Examine range characteristics:

``````    \$range->length;              # 8
\$range->size;                # 10

\$range->is_in_range(100);    # 0
\$range->is_in_range(18);     # 1, 16, 20``````

# DESCRIPTION

An instance of the Number::RangeTracker class is used to keep track of a set of numerical ranges. Ranges can be added to and removed from this collection of ranges. Overlapping ranges are collapsed to form a single, longer range. Ranges can be manipulated, examined, and output in a variety of ways.

While some other modules associate values with a range of keys (see "SEE ALSO"), the objective of Number::RangeTracker is to quickly and easily monitor the integers on a number line that are covered by at least one range. Number::RangeTracker performs significantly faster than other modules that have similar functions (see "SEE ALSO").

new

Initializes a new Number::RangeTracker object.

add( START, END )

Add one or more ranges. This can be used multiple times to add ranges to the object. Ranges can be added in several ways. The following are equivalent.

``````    \$range->add( [ 1, 10 ], [ 16, 20 ] );
\$range->add( 1, 10, 16, 20 );
\$range->add( '1..10', '16..20' );``````
remove( START, END )

Remove one or more ranges from the current set of ranges. This can be used multiple times to remove ranges from the object. Ranges can be removed with the same syntax used for adding ranges.

collapse

When ranges are added or removed, overlapping ranges are not collapsed until necessary. This allows range Number::RangeTracker to be very fast.

Ranges can be manually collapsed to avoid memory issues when working with very large amounts of ranges. In one test, a million overlapping ranges required ~100 MB of memory. This requirement was cut drastically by collapsing ranges after every 100,000th range was added.

Ranges are automatically collapsed (and merged or removed where appropriate) (1) before ranges are added (if there are ranges still waiting to be removed) and (2) before each of the following methods is executed.

length

Returns the total length of all ranges combined.

size

Returns the total number of elements (i.e., integers) of all ranges.

is_in_range( VALUE )

Test whether a VALUE is contained within one of the ranges. Returns 0 for a negative result. Returns a list of three numbers for a positive result: 1, start position of the containing range, end position of the containing range.

output

Returns all ranges sorted by their start positions. In list context, returns a list of all ranges sorted by start positions. This is suitable for populating a hash, an array, or even another range object. In scalar context, returns a string of ranges formatted as: `1..10,16..20`.

integers

Returns each integer contained within the ranges. In list context, returns a sorted list. In scalar context, returns a sorted, comma-delimited string of integers.

complement( UNIVERSE_START, UNIVERSE_END )

Returns the complement of a set of ranges. The output is in list context sorted by range start positions.

``````    my \$original_range = Number::RangeTracker->new;
\$original_range->add( [ 11, 20 ], [ 41, 60 ], [ 91, 110 ] );

my %complement = \$original_range->complement;
# -inf => 10,
# 21   => 40,
# 61   => 90,
# 111  => +inf``````

UNIVERSE_START and UNIVERSE_END can be used to specify a finite subset of the 'universe' of numbers (defaults are -/+ infinity. The complement ranges are bounded by these values.

``````    %complement = \$original_range->complement( 1, 50 );
# 1  => 10,
# 21 => 40``````

A new object with the complement of a set of ranges can be created quickly and easily.

``````    my \$complement_range = Number::RangeTracker->new;

Monitor the integers covered by at least one range

Although there is some functional overlap between this module, Number::Range, and Range::Object::Serial, Number::RangeTracker is significantly faster.

It takes less than one second for Number::RangeTracker to add 100,000 overlapping ranges. Over this same period of time, Number::Range and Range::Serial::Object are only able to add 1,000 and 300 ranges, respectively.

Some tasks require even higher throughput. When adding 1 million overlapping ranges, Number::Range took >250 times as long as Number::RangeTracker (35 min 31 sec vs. 8 sec). Range::Object::Serial slows exponentially as ranges are added and, therefore, it was not feasible to test this many ranges.

Ranges with strandedness (like double-stranded DNA or mile posts on a two-way road)

Bio::Range

Compare numbers in an imprecision-tolerant manner

Number::Tolerant

Named ranges

# SOURCE AVAILABILITY

The source code is on Github: https://github.com/mfcovington/Number-RangeTracker

# AUTHOR

Michael F. Covington, <mfcovington@gmail.com>

# BUGS

Please report any bugs or feature requests at https://github.com/mfcovington/Number-RangeTracker/issues.

# INSTALLATION

To install this module from GitHub using cpanm:

``    cpanm git@github.com:mfcovington/Number-RangeTracker.git``

Alternatively, download and run the following commands:

``````    perl Build.PL
./Build
./Build test
./Build install``````

# SUPPORT AND DOCUMENTATION

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

``    perldoc Number::RangeTracker``

Copyright 2014 Michael F. Covington.

This program is free software; you can redistribute it and/or modify it under the terms of the the Artistic License (2.0). You may obtain a copy of the full license at: