NAME
Tie::Array::Cavity - create an array where key are aggregated by step (
and optionally could start with an offset )
VERSION
Version 0.02
SYNOPSIS
A Tie array module where the keys ( indexes ) are like a cavity bucket
and collect all the keys from a specific neighbor range
Perhaps a little code snippet.
use Tie::Array::Cavity;
my $tied = tie my @a, 'Tie::Array::Cavity' , 10 , 5;
$a[1] = 1;
$a[15] = 15;
$a[25]=25;
$a[24]=240;
$a[31]=31;
$a[40]=40;
Result:
[
1,
15,
240,
31,
40
];
as a consequence,
$a[1];
and
$a[2];
refer to the same element of the array
In the previous code
$a[25]=25;
set the the 3 element with the value 25,but
$a[24]=240;
over write the 3 element with the value 240.
!!!!! BECARE !!!!!
lvalue update are not working as expected.
In the example above,
$a[24]++;
is setting the second element of the array with '1' because fetching the value $a[24] return the 24 element of the array.
It is "by design" to allow normal iteration on the array ( e.g. foreach ( @a ) or Dumper(\@a ) )
EXPORT
A list of functions that can be exported. You can delete this section
if you don't export anything, such as for a purely object-oriented
module.
SUBROUTINES/METHODS
TIEARRAY
my $tied = tie my @a, 'Tie::Array::Cavity' , 10 , 5;
Tie::Array::Cavity tie an array where the keys are in a range Two extra
parameters are allowed: 1) the granularity of the key range ( default =
0 ) 2) the initial offset ( default = 0 )
STORE
Add an element in the array at the ARRAY index with the cavity
behavior;
my $tied = tie my @a, 'Tie::Array::Cavity' , 10 , 5; $myarray[31] ,
45646;
store 45646 at the 3 place in the array
[
...,
...,
45646,
...,
]
STORESIZE this
Sets the total number of items in the tied array associated with object
this.
FETCHSIZE this
Returns the total number of items in the tied array associated with
object this. (Equivalent to scalar(@array)).
FETCHCAVITY this , index
Retrieve the value in index for the tied array associated with object
this. But the index is calculated with the cavity feature.
FETCHKEY this , index
Return the calculated real key used by the cavity feature.
FETCHKEYCAVITY this , index
Return the calculated cavity key related to a normal array index.
FETCH this , index
Retrieve the value in index for the tied array associated with object
this.
POP this
Remove the last element of the array and return it.
SHIFT this
Remove the first element of the array and return it.
PUSH this, LIST
Append elements of LIST to the array.
UNSHIFT this, LIST
Insert LIST elements at the beginning of the array, moving existing
elements up to make room.
EXISTSCAVITY this, key
Verify that the element at index key exists in the tied array this. The
key is using the cavity feature.
EXISTS this, key
Verify that the element at index key exists in the tied array this.
DELETECAVITY this, key
Delete the element at index key from the tied array this. The key is
using the cavity feature.
DELETE this, key
Delete the element at index key from the tied array this.
SPLICECAVITY this, offset, length, LIST
Perform the equivalent of splice on the array.
offset is optional and defaults to zero, negative values count back
from the end of the array.
length is optional and defaults to rest of the array.
LIST may be empty.
Returns a list of the original length elements at offset.
The offset and length is using the cavity feature.
SPLICE this, offset, length, LIST
Perform the equivalent of splice on the array.
offset is optional and defaults to zero, negative values count back
from the end of the array.
length is optional and defaults to rest of the array.
LIST may be empty.
Returns a list of the original length elements at offset.
USAGE
One of the useful usage of this module is for aggregating data coming
for a time series by some slice. Example: You've got a lot of data
polled each second for a day, and you would like to aggregate the
result by 5 minutes starting at the beginning of the day:
my %data = ( 1351551600 => 10, 1351551601 => 15, 1351551950 => 5 );
my $tied1= tie my @d, 'Tie::Array::Cavity' , 300 ,1351551600 ;
my $start = 1351551600;
foreach my $t ( keys %data )
{
$d[$t]= $tied1->FETCHCAVITY($t)+ $data{ $t };
}
say Dumper(\@d);
AUTHOR
DULAUNOY Fabrice, <fabrice at dulaunoy.com>
BUGS
Please report any bugs or feature requests to bug-tie-array-Cavity at
rt.cpan.org, or through the web interface at
http://rt.cpan.org/NoAuth/ReportBug.html?Queue=Tie-Array-Cavity. I will
be notified, and then you'll automatically be notified of progress on
your bug as I make changes.
SUPPORT
You can find documentation for this module with the perldoc command.
perldoc Tie::Array::Cavity
You can also look for information at:
* RT: CPAN's request tracker (report bugs here)
http://rt.cpan.org/NoAuth/Bugs.html?Dist=Tie-Array-Cavity
* AnnoCPAN: Annotated CPAN documentation
http://annocpan.org/dist/Tie-Array-Cavity
* CPAN Ratings
http://cpanratings.perl.org/d/Tie-Array-Cavity
* Search CPAN
http://search.cpan.org/dist/Tie-Array-Cavity/
ACKNOWLEDGEMENTS
LICENSE AND COPYRIGHT
Copyright 2012 DULAUNOY Fabrice.
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.