/ 
Tie-Array-CSV-0.08
River stage one • 1 direct dependent • 1 total dependent
/ Tie::Array::CSV

NAME

Tie::Array::CSV - A tied array which combines the power of Tie::File and Text::CSV

SYNOPSIS

use strict; use warnings;
use Tie::Array::CSV;
tie my @file, 'Tie::Array::CSV', 'filename';

print $file[0][2];
$file[3][5] = "Camel";

DESCRIPTION

This module allows an array to be tied to a CSV file for reading and writing. The array is a standard Perl 2D array (i.e. an array of array references) which gives access to the row and column of the user's choosing. This is done using the well established modules:

This module was inspired by Tie::CSV_File which (sadly) hasn't been maintained. It also doesn't attempt to do any of the parsing (as that module did), but rather passes all of the heavy lifting to other modules.

Note that while the Tie::File prevents the need to read in the entire file, while in use, a parsed row IS held in memory.

CONSTRUCTORS

Since version 0.04 both constructors allow the options that version 0.03 only offered for the new constructor. The constructors must be passed a file name, either as the first argument, or as the value to the option key file. Options may be passed as key-value pairs or as a hash reference. This yields the many ways of calling the constructors shown below, one for every taste.

N.B. Should a lone argument filename and a file option key both be passed to the constructor, the lone argument wins.

tie Constructor

As with any tied array, the construction uses the tie function. Basic usage is as follows:

tie my @file, 'Tie::Array::CSV', 'filename';

which would tie the lexically scoped array @file to the file filename using this module. Following the first two arguements to tie, one may optionally pass a key-value pairs or a hashref containing additional configuration or even file specification.

tie my @file, 'Tie::Array::CSV', 'filename', { opt_key => val, ... };
tie my @file, 'Tie::Array::CSV', 'filename', opt_key => val, ... ;
tie my @file, 'Tie::Array::CSV', { file => 'filename', opt_key => val, ... };
tie my @file, 'Tie::Array::CSV', file => 'filename', opt_key => val, ... ;

Of course, the magical Perl tie can be scary for some, for those people there is the ...

new Constructor

[ Added in version 0.03 ]

my $array = Tie::Array::CSV->new( 'filename' );
my $array = Tie::Array::CSV->new( 'filename', { opt_key => val, ... });
my $array = Tie::Array::CSV->new( 'filename', opt_key => val, ... );
my $array = Tie::Array::CSV->new( file => 'filename', opt_key => val, ... );
my $array = Tie::Array::CSV->new( { file => 'filename', opt_key => val, ... } );

It only returns a reference to the tied array due to a limitations in how tie magic works.

Options

  • file - alternative method for specifing the file to tie. This is overridden by a lone filename or handle passed as the first argument to the constructor.

  • tie_file - hashref of options which are passed to the Tie::File constructor

  • text_csv - either:

    • hashref of options which are passed to the Text::CSV constructor

    • an object which satisfies isa('Text::CSV') (added in version 0.05)

  • sep_char - for ease of use, a sep_char option may be specified, which is passed to the Text::CSV constructor. This option overrides a corresponding entry in the text_csv pass-through hash.

Equivalent examples:

tie my @file, 'Tie::Array::CSV', 'filename', { 
  tie_file => {}, 
  text_csv => { sep_char => ';' },
};

tie my @file, 'Tie::Array::CSV', 'filename', sep_char => ';';

Note that as of version 0.05 the functionality from the former hold_row option has been separated into its own subclass module Tie::Array::CSV::HoldRow. If deferring row operations is of interest to you, please see that module.

ERRORS

For simplicity this module croaks on all almost all errors, which are trappable using a $SIG{__DIE__} handler. Modifing a severed row object issues a warning.

CAVEATS

  • Much of the functionality of normal arrays is mimicked using Tie::Array. The interaction of this with Tie::File should be mentioned in that certain actions may be very inefficient. For example, (un)shift-ing the first row of data will probably involve Tie::Array asking Tie::File to move each row up one line, one-by-one. As a note, the intra-row (un)shift does not suffer this problem.

  • At one time, some effort was been made to allow for fields which contain linebreaks. Quickly it became clear that linebreaks would change line numbers used for row access by Tie::File. Attempts to compensate for this, unfortunately, moved the module far from its stated goals, and therefore far less powerful for its intended purposes. The decision has been made (for now) not to support such files.

SEE ALSO

SOURCE REPOSITORY

http://github.com/jberger/Tie-Array-CSV

AUTHOR

Joel Berger, <joel.a.berger@gmail.com>

CONTRIBUTORS

Christian Walde (Mithaldu) Graham Ollis (plicease)

COPYRIGHT AND LICENSE

Copyright (C) 2013 by "AUTHOR" and "CONTRIBUTORS".

This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself.