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::CavityYou can also look for information at:
RT: CPAN's request tracker (report bugs here)
AnnoCPAN: Annotated CPAN documentation
CPAN Ratings
Search CPAN
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.