mic array

Array is an easy-to-use animation program. If you know the childrens toy where you poke transparent colored pegs through a backlit screen (LiteBrite), Array uses the same idea, but with multiple screens, to create animation.

You color points on a sequence of frames. There are various functions to manipulate the points. You can play, save, and reload your animation. You can export your animation as a Flash movie.

Array::Iterator is a simple class for iterating over Perl arrays.

SYNOPSIS

use Array::Iterator;

# create an iterator with an array
my $i = Array::Iterator->new(1 .. 100);

# create an iterator with an array reference
my $i = Array::Iterator->new(@array);

# create an iterator with a hash reference
my $i = Array::Iterator->new({ __array__ => @array });

# a base iterator example
while ($i->hasNext()) {
if ($i->peek() < 50) {
# ... do something because
# the next element is over 50
}
my $current = $i->next();
# ... do something with current
}

# shortcut style
my @accumulation;
push @accumulation => { item => $iterator->next() } while $iterator->hasNext();

# C++ ish style iterator
for (my $i = Array::Iterator->new(@array); $i->hasNext(); $i->next()) {
my $current = $i->current();
# .. do something with current
}

# common perl iterator idiom
my $current;
while ($current = $i->getNext()) {
# ... do something with $current
}

This class provides a very simple iterator interface. It is is uni-directional and can only be used once. It provides no means of reverseing or reseting the iterator. It is not recommended to alter the array during iteration, however no attempt is made to enforce this (although I will if I can find an efficient means of doing so). This class only intends to provide a clear and simple means of generic iteration, nothing more (yet).

Array::Utils module contains small utils for array manipulation.

SYNOPSIS

use Array::Utils qw(:all);

my @a = qw( a b c d );
my @b = qw( c d e f );

# symmetric difference
my @diff = array_diff(@a, @b);

# intersection
my @isect = intersect(@a, @b);

# unique union
my @unique = unique(@a, @b);

# check if arrays contain same members

if ( !array_diff(@a, @b) ) {
# do something
}

FUNCTIONS

unique

Returns an array of unique items in the arguments list.

intersect

Returns an intersection of two arrays passed as arguments.

array_diff

Return symmetric difference of two arrays passed as arguments

Array-util project was tested on: It gives you an overview of all logical and physical drives, including basic information on sizes etc. It is supposed to become a configuration tool in the future. Note that it only works with SmartArray driver version 1.0.1+

Array-util project was tested on:

· Compaq Proliant 2500 with SmartArray 2DH
· Compaq Proliant 1600 with SmartArray 2DH
· Compaq Proliant ML350 with an additional Smart Array 431-Controller (thanks to Christian Bauer)
· Compaq Proliant DL380 with Internal SmartArray controller (thanks to Jason Sturgeon)
· Compaq Proliant ML370 with Integrated SmartArray (thanks to Brian Rossmeisl)
· Compaq Proliant 5500 with a SmartArray 3200 (thanks to Andrew A. Neuschwander)
· Compaq Proliant 1850R with a SmartArray 3200 (thanks to Brian Towles)
· Compaq Proliant 6400R with a SmartArray 3200 (thanks to Brian Towles)
· Compaq Proliant 3000 with a SmartArray 3200 (thanks to Brian Towles)
· Compaq Proliant DL580 with two SmartArray 4200 (thanks to Dietmar Stein)

Known bugs:

Array-util: Blinking is not working on a DL380.
Array-util: Hotspares are not listed in array-util.
Array-util: There is no progess indicator of the rebuild process.

Panopticum Array is an After Effects plug-in that adds motion filters to images.

Arrary
The main purpose of the Panopticum Array module is multiple copying of layers from your After Effects project with progressive changing of their geometric properties. Here you may create very sophisticated geometric patterns that may be used either for further use in your composition or for transparency masks. Those masks you might want to use in cutting through of other objects, layers or texts.

Digital Matrix
This module was made for creation of backgrounds composed of numbers and letters. The background figures may float, change according to preset law (suddenly or fluently by morphing). You can assign your own set of matrix elements, their size, font, color, etc. You can also change the interval between matrix lines and columns, regulate number of layers in three-dimensional array, its depth, perspective, etc.

Digital Chaos
With the help of this module you will be able to create beautiful animated scenes containing random arrangement of text symbols or colorful balls.

AVL Array is an STL-like container for C++ that fills the gap between vector (or deque) and list, providing both fast random access and fast insertion/removal, all O(log n).

This is not a map; in an avl_array, the "keys" always range from 0 to size-1, and they automatically change on insertion or removal. As a sequence container, like vector and list, it respects the order of elements.

Whats New in This Release:

· documentation
· source reorganized for readability
· compliance with higher standards
· performance improvements

Array::PatternMatcher is a pattern matching for arrays.

SYNOPSIS

This section inlines the entire test suite. Please excuse the ok()s.

use Array::PatternMatcher;

Matching logical variables to input stream

# 1 - simple match of logical variable to input
my $pattern = AGE ;
my $input = 969 ;
my $result = pat_match ($pattern, $input, {} ) ;
ok($result->{AGE}, 969) ;

# 2 - if binding exists, it must equal the input
$input = 12;
my $new_result = pat_match ($pattern, $input, $result) ;
ok(!defined($new_result)) ;

# 3 - bind the pattern logical variables to the input list

$pattern = [qw(X Y)] ;
$input = [ 77, 45 ] ;
my $result = pat_match ($pattern, $input, {} ) ;
ok($result->{X}, 77) ;
Matching segments (quantifying) portions of the input stream
# 1
{
my $pattern = [a, [qw(X *)], d] ;
my $input = [a, b, c, d] ;

my $result = pat_match ($pattern, $input, {} ) ;
ok ("@{$result->{X}}","b c") ;
}

# 2
{

my $pattern = [a, [qw(X *)], [qw(Y *)], d] ;
my $input = [a, b, c, d] ;
my $result = pat_match ($pattern, $input, {} ) ;
ok ("@{$result->{Y}}","b c") ;

}
# 3
{
my $pattern = [a, [qw(X +)], d] ;
my $input = [a, b, c, d] ;
ok ("@{$result->{X}}","b c") ;
}
# 4
{
my $pattern = [ a, [qw(X ?)], c ] ;
my $input = [ a, b, c ] ;
my $result = pat_match ($pattern, $input, {} ) ;
ok ("$result->{X}","b") ;
}
# 5
{
my $pattern = [ qw(X OP Y is Z),
[
sub { "($_->{X} $_->{OP} $_->{Y}) == $_->{Z}" },
IF?
]
] ;
my $input = [qw(3 + 4 is 7) ] ;
my $result = pat_match ($pattern, $input, {} ) ;
ok ($result) ;
}
Single-matching:
Take a single input and a series of patterns and decide which pattern
matches the input:

# 1 - Here all input patterns must match the input

{
my @pattern ;
push @pattern, [ qw(X Y) ] ;
push @pattern, [ qw(22 Z ) ] ;
push @pattern, [ qw(M 33) ] ;

my $input = [ qw(22 33) ] ;

my $meta_pattern = [ AND?, @pattern ] ;

# if no bindings, add a binding between pattern and input
my $result = pat_match ($meta_pattern, $input, {} ) ;
ok ($result->{Z},33) ;
}

# 2 - Here, any one of the patterns must match the input

{
my @pattern ;
push @pattern, [ qw(99 22) ] ;
push @pattern, [ qw(33 22) ] ;
push @pattern, [ qw(44 3) ] ;
push @pattern, [ qw(22 Z) ] ;

my $input = [ qw(22 33) ] ;

my $meta_pattern = [ OR?, @pattern ] ;

# if no bindings, add a binding between pattern and input
my $result = pat_match ($meta_pattern, $input, {} ) ;
ok ($result->{Z},33) ;
}

# 3 - Here, none of the patterns must match the input

{
my @pattern ;
push @pattern, [ qw(99 22) ] ;
push @pattern, [ qw(33 22) ] ;
push @pattern, [ qw(44 3) ] ;
push @pattern, [ qw(22 Z) ] ;

my $input = [ qw(22 33) ] ;

my $meta_pattern = [ NOT?, @pattern ] ;

# if no bindings, add a binding between pattern and input
my $result = pat_match ($meta_pattern, $input, {} ) ;
ok (scalar keys %$result == 0) ;
}

# 4 - here the input must satisfy the predicate
{
sub numberp { $_[0] =~ /d+/ }

my $pattern = [ qw(X age), [qw(IS? N), νmberp] ] ;
my $input = [ qw(Mary age), thirty-four ] ;

# if no bindings, add a binding between pattern and input
my $result = pat_match ($pattern, $input, {} ) ;
ok (!defined($result));
}

# 5 - same thing, but this time a failing result ---
# not undef because it is the return val of numberp
{
sub numberp { $_[0] =~ /d+/ }

my $pattern = [ qw(X age), [qw(IS? N), νmberp] ] ;
my $input = [ qw(Mary age), 34 ] ;
my $result = pat_match ($pattern, $input, {} ) ;

ok ($result->{N},34) ;
}
Segment-matching:
Match a chunk of the input stream using *, +, ?

# 1 - * is greedy in this case, but not with 2 consecutve * patterns
{
my $pattern = [a, [qw(X *)], d] ;
my $input = [a, b, c, d] ;

# if no bindings, add a binding between pattern and input
my $result = pat_match ($pattern, $input, {} ) ;
warn sprintf "X*RETVAL: %s", Data::Dumper::Dumper($result) ;
ok ("@{$result->{X}}","b c") ;
}
# 2 - X* gets nothing, Y* gets all it can:
{

my $pattern = [a, [qw(X *)], [qw(Y *)], d] ;
my $input = [a, b, c, d] ;

# if no bindings, add a binding between pattern and input
my $result = pat_match ($pattern, $input, {} ) ;
warn sprintf "X*Y*RETVAL: %s", Data::Dumper::Dumper($result) ;
ok ("@{$result->{Y}}","b c") ;

}
# 3 - samething , but require at least one match for X
{
my $pattern = [a, [qw(X +)], d] ;
my $input = [a, b, c, d] ;

my $result = pat_match ($pattern, $input, {} ) ;
warn sprintf "RETVAL: @{$result->{X}}" ;
ok ("@{$result->{X}}","b c") ;
}
# 4 - require 0 or 1 match for X
{
my $pattern = [ a, [qw(X ?)], c ] ;
my $input = [ a, b, c ] ;


my $result = pat_match ($pattern, $input, {} ) ;

ok ("$result->{X}","b") ;
}
# 5 - evaluate a sub on the fly after match
{
my $pattern = [ qw(X OP Y is Z),
[
sub { "($_->{X} $_->{OP} $_->{Y}) == $_->{Z}" },
IF?
]
] ;
my $input = [qw(3 + 4 is 7) ] ;

my $result = pat_match ($pattern, $input, {} ) ;

ok ($result) ;
}
# --- 6 same thing, but fail
{
my $pattern = [ qw(X OP Y is Z),
[
sub { "($_->{X} $_->{OP} $_->{Y}) == $_->{Z}" },
IF?
]
] ;
my $input = [qw(3 + 4 is 8) ] ;

my $result = pat_match ($pattern, $input, {} ) ;
warn sprintf "IF_RETVAL2: *%s*", Data::Dumper::Dumper($result);
ok ($result eq ) ;
}

Tie::Array::PackedC is a tie a Perl array to a C-style array (packed; elements of a single, simple data type).

SYNOPSIS

use Tie::Array::PackedC qw(packed_array packed_array_string);
my $ref=packed_array(1,2,3,4);
my $ref2=packed_array_string(my $s,1,2,3,4);

use Tie::Array::PackedC Double=>d;
tie my @array,Tie::Array::PackedC::Double,1..10;
$array[0]=1.141;

Provides a perl array interface into a string containing a C style array. In other words the string is equivelent to the string that would be returned from the equivelent pack command (defaulting to pack type "l!") using a normal array of the same values. Eg:

my @foo=(1..10);
my $string=pack "l!*",@foo;

leaves $string in basically the same condition as

my (@foo,$string);
tie @foo,Tie::Array::PackedC,$string,1..10;

Its only basically the same and not exactly the same because the tie version may be longer due to preallocation.

Tie::Array::RestrictUpdates can limit the number of times you change elements in an array.

SYNOPSIS

use Tie::Array::RestrictUpdates;

tie @foo,"Tie::Array::RestrictUpdates",1;
# Default limit is 1.
# Every element from the array can only be changed once
@foo = qw(A B C D E);
for(0..4) { $foo[$_] = lc $foo[$_]; }
print join("-",@foo);
# This will print A-B-C-D-E and a bunch of warnings

-or-

use Tie::Array::RestrictUpdates;

tie @foo,"Tie::Array::RestrictUpdates",[1,2,3,4];
# This forces the limits of the first 3 indexes
# This also forces any extra elements from the array to have a 0 limit
# and therefor be unchangable/unsettable
@foo = qw(A B C D E);
for(0..3) { $foo[$_] = lc $foo[$_]; }
for(0..3) { $foo[$_] = uc $foo[$_]; }
for(0..3) { $foo[$_] = lc $foo[$_]; }
for(0..3) { $foo[$_] = uc $foo[$_]; }
print join("-",@foo);
# This will print A-b-C-d and a bunch of warnings

Tie::FlatFile::Array is a Perl extension which treats a flatfile database as an array of arrays.

This module allows the programmer to treat a flatfile database as as array of arrays. For example, lets say you have a datafile that has fixed-length records like so:

Field-name Type
URL ASCII characters, length 30
Referals Integer, 4 bytes, binary in network order

If you were going to use pack to create a record like this, youd use a format string of A30N. Since Tie::FlatFile::Array does the packing and unpacking behind the scenes, you would use that pack format string in the call to tie:

tie @flat, Tie::FlatFile::Array, data.file,
O_RDWR | O_CREAT, 0644, { packformat => A30N }
or die("Tie failure: $!");

To insert an item into the data file, you would assign an array reference to one of the arrays elements like so:

$flat[0] = [ www.yahoo.com, 3601 ];

Set::Array Perl module contains arrays as objects with lots of handy methods (including Set comparisons) and support for method chaining.

SYNOPSIS

my $sao1 = Set::Array->new(1,2,4,"hello",undef);
my $sao2 = Set::Array->new(qw(a b c a b c));
print $sao1->length; # prints 5
$sao2->unique->length->print; # prints 3

Set::Array allows you to create arrays as objects and use OO-style methods on them. Many convenient methods are provided here that appear in the FAQs, the Perl Cookbook or posts from comp.lang.perl.misc. In addition, there are Set methods with corresponding (overloaded) operators for the purpose of Set comparison, i.e. +, ==, etc.

The purpose is to provide built-in methods for operations that people are always asking how to do, and which already exist in languages like Ruby. This should (hopefully) improve code readability and/or maintainability. The other advantage to this module is method-chaining by which any number of methods may be called on a single object in a single statement.

OBJECT BEHAVIOR

The exact behavior of the methods depends largely on the calling context.
Here are the rules:

* If a method is called in void context, the object itself is modified.
* If the method called is not the last method in a chain (i.e. its called in object context), the object itself is modified by that method regardless of the final context or method call.
* If a method is called in list or scalar context, a list or list refererence is returned, respectively. The object itself is NOT modified.

Heres a quick example:

my $sao = Set::Array->new(1,2,3,2,3);
my @uniq = $sao->unique(); # Object unmodified. @uniq contains 3 values.
$sao->unique(); # Object modified, now contains 3 values

Here are the exceptions:

* Methods that report a value, such as boolean methods like exists() or other methods such as at() or as_hash(), never modify the object.
* The methods clear(), delete(), delete_at(), and splice will always modify the object. It seemed much too counterintuitive to call these methods in any context without actually deleting/clearing/substituting the items!
* The methods shift() and pop() will modify the object AND return the value that was shifted or popped from the array. Again, it seemed much too counterintuitive for something like $val = $sao->shift to return a value while leaving the objects list unchanged. If you really want the first or last value without modifying the object, you can always use the first() or last() method, respectively.
* The join() method always returns a string and is really meant for use in conjunction with the print() method.

BOOLEAN METHODS

exists(val) - Returns 1 if val exists within the array, 0 otherwise. If no value (or undef) is passed, then this method will test for the existence of undefined values within the array.
is_empty() - Returns 1 if the array is empty, 0 otherwise. Empty is defined as having a length of 0.

STANDARD METHODS

at(index) - Returns the item at the given index (or undef). A negative index may be used to count from the end of the array. If no value (or undef) is specified, it will look for the first item that is not defined.

clear() - Empties the array (i.e. length becomes 0). You may pass a 1 to this method to set each element of the array to undef rather than truly empty it.

compact() - Removes undefined elements from the array.

count(?val?) - Returns the number of instances of val within the array. If val is not specified (or is undef), the method will return the number of undefined values within the array.

delete(list) - Deletes all items within list from the array that match. This method will crash if list is not defined. If your goal is to delete undefined values from your object, use the compact() method instead.

delete_at(index, ?index?) - Deletes the item at the specified index. If a second index is specified, a range of items is deleted. You may use -1 or the string end to refer to the last element of the array.

duplicates - Returns a list of N-1 elements for each element N in the set. For example, if you have set "X X Y Y Y", this method would return a the list "X Y Y".

fill(val,?start?,?length?) - Sets the selected elements of the array (which may be the entire array) to val. The default value for start is 0. If length is not specified the entire array, however long it may be at the time of the call, will be filled. Alternatively, a quoted integer range may be used.

e.g. $sao->fill(x,3-5);

The array length/size may not be expanded with this call - it is only meant to fill in already-existing elements.

first() - Returns the first element of the array (or undef).

flatten() - Causes a one-dimensional flattening of the array, recursively. That is, for every element that is an array (or hash, or a ref to either an array or hash), extract its elements into the array.

e.g. my $sa = Set::Array->new([1,3,2],{one=>a,two=>b},x,y,z);

$sao->flatten->join(,)->print; # prints "1,3,2,one,a,two,b,x,y,z"

foreach(sub ref) - Iterates over an array, executing the subroutine for each element in the array. If you wish to modify or otherwise act directly on the contents of the array, use $_ within your sub reference.

e.g. To increment all elements in the array by one...

$sao->foreach(sub{ ++$_ });

get - Alias for the indices() method.

index(val) - Returns the index of the first element of the array object that contains val. Returns undef if no value is found.

Note that there is no dereferencing here so if youre looking for an item nested within a ref, use the flatten method first.

indices(val1,?val2?, ?val...?) - Returns an array consisting of the elements at the specified indices or undef if the element is out of range.

A range may also be used. It must be a quoted string in 0..3 format.

join(?char?) - Joins the individual elements of the list into a single string with the elements separated by the value of char. Useful in conjunction with the print() method. If no character is specified, then char defaults to a comma.

e.g. $sao->join(-)->print;

last() - Returns the last element of the array (or undef).

length() - Returns the number of elements within the array.

max() - Returns the maximum value of an array. No effort is made to check for non-numeric data.

pack(template) - Packs the contents of the array into a string (in scalar context) or a single array element (in object or void context).

pop() - Removes the last element from the array. Returns the popped element.

print(?1?) - Prints the contents of the array. If a 1 is provided as an argument, the output will automatically be terminated with a newline.

This also doubles as a contents method, if you just want to make a copy of the array, e.g. my @copy = $sao->print;

Can be called in void or list context, e.g.

$sao->print(); # or... print "Contents of array are: ", $sao->print();

push(list) - Adds list to the end of the array, where list is either a scalar value or a list. Returns an array or array reference in list or scalar context, respectively. Note that it does not return the length in scalar context. Use the length method for that.

reverse() - Reverses the order of the contents of the array.

rindex(val) - Similar to the index() method, except that it returns the index of the last val found within the array.

set(index,value) - Sets the element at index to value, replacing whatever may have already been there.

shift() - Shifts the first element of the array and returns the shifted element.

sort(?coderef?) - Sorts the contents of the array in alphabetical order, or in the order specified by the optional coderef. Use your standard $a and $b variables within your calling program, e.g:

my $sao = Set::Array->new( { name => Berger, salary => 20000 }, { name => Berger, salary => 15000 }, { name => Vera, salary => 25000 }, );
my $subref = sub{ $b->{name} cmp $a->{name} || $b->{salary} $a->{salary} };
$sao14->sort($subref)->flatten->join->print(1);

splice(?offset?,?length?,?list?) - Splice the array starting at position offset up to length elements, and replace them with list. If no list is provided, all elements are deleted. If length is omitted, everything from offset onward is removed.

Returns an array or array ref in list or scalar context, respectively. This method always modifies the object, regardless of context. If your goal was to grab a range of values without modifying the object, use the indices method instead.

unique() - Removes/returns non-unique elements from the list.

unshift(list) - Prepends a scalar or list to array. Note that this method returns an array or array reference in list or scalar context, respectively. It does not return the length of the array in scalar context. Use the length method for that.

ODDBALL METHODS

as_hash() - Returns a hash based on the current array, with each even numbered element (including 0) serving as the key, and each odd element serving as the value. This can be switched by using the key_order option and setting it to odd, in which case the even values serve as the values, and the odd elements serve as the keys. The default is even.

Of course, if you dont care about insertion order, you could just as well do something like, $sao-reverse->as_hash;>

Carp::croaks if the array contains an odd number of elements. This method does not actually modify the object itself in any way. It just returns a plain hash in list context or a hash reference in scalar context. The reference is not blessed, therefore if this method is called as part of a chain, it must be the last method called.

impose(?append/prepend?,string) - Appends or prepends the specified string to each element in the array. Specify the method by using either the keyword append or prepend. The default is append.

randomize() - Randomizes the order of the elements within the array.

rotate(direction) - Moves the last item of the list to the front and shifts all other elements one to the right, or vice-versa, depending on what you pass as the direction - ftol (first to last) or ltof (last to first). The default is ltof.

e.g. my $sao = Set::Array->new(1,2,3);

$sao->rotate(); # order is now 3,1,2

$sao->rotate(ftol); # order is back to 1,2,3

Array Designer project can help design thousands of efficient, highly specific oligos to make microarrays for SNP genotyping and expression studies with the click of a button.

For investigating gene control elements in the post-sequencing era, the software designs tiling arrays for interrogating intragenic and intergenic regions and now the software also designs resequencing arrays for analysis of large genomic sequences and genetic variation within the clinical trial population.

Here are some key features of "Array Designer":

· Oligo microarray software: Array Designer designs highly specific oligo microarray for SNP genotyping and expression studies.
· Oligo microarray design software which helps you design probes for expression and SNP studies.
· Array Designer is a highly flexible and scalable microarray software, for designing oligos/primers for large projects.
· Array Designer is a microarray software which offers a high-throughput, greatly automated approach for designing highly specific optimal oligonucleotide probes for microarray experiments.
· cDNA microarray design: Array Designer by default, uses optimized design parameters for cDNA microarray design.
· For DNA microarray design, the carefully chosen default parameters help make the design a success.
· Array Designer, with its highly sophisticated algorithm, may be the best available dna microarray software for microarray design.
· Whole genome array-Whole genome arrays have been useful for studying the poorly understood aspects of trancriptome, natural antisense transcript because they can simultaneously monitor gene expression on both strands of genome
· Tiling array- Tiling array are used to investigate transcription factor binding sites TFBS, not only upstream of genes but also in intronic and intergenic regions.
· Resequencing arrays- In addition to standard probes, Array Designer also designs resequencing arrays useful for analysis of large genomic sequences and genetic variation within the clinical trial population.
· Flexible input formats- Supports sequences in GenBank, FASTA. Loads multiple sequences from a single GenBank or FASTA format file.
· Standard PCR Reaction Conditions- Optimizes PCR primers on all sequences to amplify with uniform reaction conditions.
· Multiple probes- Designs the best probe per sequence or multiple probes per sequence for increased accuracy of detection.
· SNP detection- Designs SNP probes for both hybridization and primer extension detection.
· Flexible Hybridization Probe Locations- Probes can be designed to span each site, or can have 3 end anchored at each site, or can be optimized within a specified region around the site.

SYNOPSIS

use Array::Compare;

my $comp1 = Array::Compare->new;
$comp->Sep(|);
$comp->Skip({3 => 1, 4 => 1});
$comp->WhiteSpace(0);
$comp->Case(1);

my $comp2 = Array::Compare->new(Sep => |,
WhiteSpace => 0,
Case => 1,
Skip => {3 => 1, 4 => 1});

my @arr1 = 0 .. 10;
my @arr2 = 0 .. 10;

$comp1->compare(@arr1, @arr2);
$comp2->compare(@arr1, @arr2);

If you have two arrays and you want to know if they are the same or different, then Array::Compare will be useful to you.
All comparisons are carried out via a comparator object. In the simplest usage, you can create and use a comparator object like this:

my @arr1 = 0 .. 10;
my @arr2 = 0 .. 10;

my $comp = Array::Compare->new;

if ($comp->compare(@arr1, @arr2)) {
print "Arrays are the samen";
} else {
print "Arrays are differentn";
}

Notice that you pass references to the two arrays to the comparison method.

Internally the comparator compares the two arrays by using join to turn both arrays into strings and comparing the strings using eq. In the joined strings, the elements of the original arrays are separated with the ^G character. This can cause problems if your array data contains ^G characters as it is possible that two different arrays can be converted to the same string.

To avoid this, it is possible to override the default separator character, either by passing and alternative to the new function

my $comp = Array::Compare->new(Sep => |);

or by changing the seperator for an existing comparator object

$comp->Sep(|);

In general you should choose a separator character that wont appear in your data.

You can also control whether or not whitespace within the elements of the arrays should be considered significant when making the comparison. The default is that all whitespace is significant. The alternative is for all consecutive white space characters to be converted to a single space for the pruposes of the comparison. Again, this can be turned on when creating a comparator object:

my $comp = Array::Compare->new(WhiteSpace => 0);

or by altering an existing object:

$comp->WhiteSpace(0);

You can also control whether or not the case of the data is significant in the comparison. The default is that the case of data is taken into account. This can be changed in the standard ways when creating a new comparator object:

my $comp = Array::Compare->new(Case => 0);

or by altering an existing object:

$comp->Case(0);

In addition to the simple comparison described above (which returns true if the arrays are the same and false if theyre different) there is also a full comparison which returns a list containing the indexes of elements which differ between the two arrays. If the arrays are the same it returns an empty list. In scalar context the full comparison returns the length of this list (i.e. the number of elements that differ). You can access the full comparision in two ways. Firstly, there is a DefFull attribute. If this is true then a full comparison if carried out whenever the compare method is called.

my $comp = Array::Compare->new(DefFull => 1);
$comp->compare(@arr1, @arr2); # Full comparison

$comp->DefFull(0);
$comp->compare(@arr1, @arr2); # Simple comparison

$comp->DefFull(1);
$comp->compare(@arr1, @arr2); # Full comparison again

Secondly, you can access the full comparison method directly

$comp->full_compare(@arr1, @arr2);

For symmetry, there is also a direct method to use to call the simple comparison.

$comp->simple_compare(@arr1, @arr2);

The final complication is the ability to skip elements in the comparison. If you know that two arrays will always differ in a particular element but want to compare the arrays ignoring this element, you can do it with Array::Compare without taking array slices. To do this, a comparator object has an optional attribute called Skip which is a reference to a hash. The keys in this hash are the indexes of the array elements and the values should be any true value for elements that should be skipped.

For example, if you want to compare two arrays, ignoring the values in elements two and four, you can do something like this:

my %skip = (2 => 1, 4 => 1);
my @a = (0, 1, 2, 3, 4, 5);
my @b = (0, 1, X, 3, X, 5);

my $comp = Array::Compare->new(Skip => %skip);

$comp->compare(@a, @b);

This should return true, as we are explicitly ignoring the columns which differ.

Of course, having created a comparator object with no skip hash, it is possible to add one later:

$comp->Skip({1 => 1, 2 => 1});

or:

my %skip = (1 => 1, 2 => 2);
$comp->Skip(%skip);

To reset the comparator so that no longer skips elements, set the skip hash to an empty hash.

$comp->Skip({});

You can also check to see if one array is a permutation of another, i.e. they contain the same elements but in a different order.

if ($comp->perm(@a, @b) {
print "Arrays are permsn";
else {
print "Nope. Arrays are completely differentn";
}

In this case the values of WhiteSpace and Case are still used, but Skip is ignored for, hopefully, obvious reasons.

Array::Unique is a tie-able array that allows only unique values.

SYNOPSIS

use Array::Unique;
tie @a, Array::Unique;

Now use @a as a regular array.

This package lets you create an array which will allow only one occurrence of any value.

In other words no matter how many times you put in 42 it will keep only the first occurrence and the rest will be dropped.

You use the module via tie and once you tied your array to this module it will behave correctly.

Uniqueness is checked with the eq operator so among other things it is case sensitive.

As a side effect the module does not allow undef as a value in the array.

EXAMPLES

use Array::Unique;
tie @a, Array::Unique;

@a = qw(a b c a d e f);
push @a, qw(x b z);
print "@an"; # a b c d e f x z

When you are collecting a list of items and you want to make sure there is only one occurrence of each item, you have several option:

1) using an array and extracting the unique elements later. You might use a regular array to hold this unique set of values and either remove duplicates on each update by that keeping the array always unique or remove duplicates just before you want to use the uniqueness feature of the array. In either case you might run a function you call @a = unique_value(@a);

The problem with this approach is that you have to implement the unique_value function (see later) AND you have to make sure you dont forget to call it. I would say dont rely on remembering this.

There is good discussion about it in the 1st edition of the Perl Cookbook of OReilly. I have copied the solutions here, you can see further discussion in the book.

----------------------------------------
Extracting Unique Elements from a List (Section 4.6 in the Perl Cookbook 1st ed.)

# Straightforward

%seen = ();
@uniq = ();
foreach $item (@list) [
unless ($seen{$item}) {
# if we get here we have not seen it before
$seen{$item} = 1;
push (@uniq, $item);
}
}

# Faster
%seen = ();
foreach $item (@list) {
push(@uniq, $item) unless $seen{$item}++;
}

# Faster but different
%seen;
foreach $item (@list) {
$seen{$item}++;
}
@uniq = keys %seen;

# Faster and even more different
%seen;
@uniq = grep {! $seen{$_}++} @list;

----------------------------------------
2) using a hash
Some people use the keys of a hash to keep the items and
put an arbitrary value as the values of the hash:

To build such a list:
%unique = map { $_ => 1 } qw( one two one two three four! );

To print it:
print join ", ", sort keys %unique;

To add values to it:
$unique{$_}=1 foreach qw( one after the nine oh nine );

To remove values:
delete @unique{ qw(oh nine) };

To check if a value is there:
$unique{ $value }; # which is why I like to use "1" as my value

(thanks to Gaal Yahas for the above examples)

There are three drawbacks I see:

1) You type more.
2) Your reader might not understand at first why did you use hash and what will be the values.
3) You lose the order.

Usually non of them is critical but when I saw this the 10th time in a code I had to understand with 0 documentation I got frustrated.

3) using Array::Unique

So I decided to write this module because I got frustrated by my lack of understanding whats going on in that code I mentioned. In addition I thought it might be interesting to write this and then benchmark it. Additionally it is nice to have your name displayed in bright lights all over CPAN ... or at least in a module.

Array::Unique lets you tie an aray to hmmm, itself (?) and makes sure the values of the array are always unique.

Since writing this I am not sure if I really recommend its usage. I would say stick with the hash version and document that the variable is aggregating a unique list of values.

4) Using real SET

There are modules on CPAN that let you create and maintain SETs. I have not checked any of those but I guess they just as much of an overkill for this functionality as Unique::Array.