NAME

Data::TableAutoSum - Table that calculates the results of rows and cols automatic

SYNOPSIS

use Data::TableAutoSum;

my $table = Data::TableAutoSum->new(rows => 10, cols => 20);
foreach my $row ($table->rows()) {
   foreach my $col ($table->cols()) {
      $table->data($row,$col) = rand();
      $table->data($row,$col) += $table->data($row-1,$col-1) 
          if $row >= 1 && $col >= 1;
   }
}

print "Row $_ has result: ",$table->rowresult($_) for $table->rows();
print "Col $_ has result: ",$table->colresult($_) for $table->cols();
print "Table has the total result: ",$table->totalresult();

ABSTRACT

Table object with automatic calculation of the row/column sums.

DESCRIPTION

This module represents a table with automatic calculation of the row/column sums.

FUNCTIONS

new(rows => $nr_of_rows, cols => $nr_of_cols)

Creates a new, zero filled table. The nr of rows and of cols must be greater than 0.

The rows and columns created are 0 .. $nr_of_rows-1 and 0 .. $nr_of_cols-1

data($row,$col,$new_value)

Get/set of data elements in the table. $new_value is optional Note, that the return value is an lvalue, so you can e.g. set a new value via $table->data($row,$col) = 4; or modify all values with

foreach my $row ($table->rows) {
  foreach my $col ($table->cols) {
    $table->data($row,$col) *= 1.05;
  }
}

rows(), cols()

These functions are returning all rows/columns in a list.

It's not possible to set rows/columns with them.

rowresult($row), colresult($col)

Returns the sum for the specified row/col.

I named the methods *result instead of *sum, as I plan to implement a possibility change the operation, e.g. to max or multiplication.

You can't change the results directly. Change the table data for that.

totalresult()

Returns the sum over all data elements. totalresult is equal to the sum of all rowresults or the sum of all colresults (of course, there could be some rounding errors).

You can't change the result directly. Change the table data for that.

EXPORT

None by default.

TODO

Named Rows/Columns

Something like this snippet:

my $table = Data::TableAutoSum->new(rows => ['New York', 'Chicago', 'L.A.'],
                                    cols => ['male', 'female', 'alien']);
                                    
$table->data('New York','male') = 1_000_000;
$table->data('L.A.', 'alien')   =   500_000;

print "Aliens in U.S.A.:", $table->colresult('alien');
print "Inhabitants of Chicagp:", $table->rowresult('Chicago');

as_string

Well, I'll need an as_string method, which will output a table in a crosstable style, e.g.

      1     2    3   Sum
0     2     9    4    15
1     7     5    3    15
2     6     1    8    15
Sum  15    15   15    45

store/read

Some methods to store and read a table to/from a file.

operation

Possibility to change the internal used operation, at the moment, only '+' is used. I'd like to give the possibility to use any other distributive, associative operation.

do

A possibility to make something with all data elements, like

$table->change(sub {$_ *= 2});

merge

A static merging method, that combines two table sets, like

my $population = Data::TableAutoSum::merge(sub {$a + $b},
                                           $female_population,
                                           $male_population);
=item overloaded operators

Some operators should be overloaded. I'd like to write something like

my $population_perc = $population / $population->totalresult;
my $euro_prices     = $dm_prices / 1.95883;

my $population = $female_population + $male_population;
my $murders_per_inhabitant = $murders / $inhabitants;

clear/fill

A clear method, that resets all values to 0 and a fill method to fill all elements with a specific value.

subtables

Something like

my $east_alien_population = $population->subtable(rows => ['Chicago', 'New York'],
                                                  cols => 'alien');

Quite an insert_subtable method seems sensful, too.

REQUIREMENTS

Params::Validate
Regexp::Common
Set::Scalar
List::Util 
    
Math::Random            # for the tests
Set::CrossProduct  
Data::Dumper       

Test::More             
Test::Exception    
Test::Builder

SEE ALSO

Data::Xtab, Data::Pivot, Table::Pivoter

AUTHOR

Janek Schleicher, <bigj@kamelfreund.de>

COPYRIGHT AND LICENSE

Copyright 2002 by Janek Schleicher

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