report-array

Easily create aggregate arrays from flat data.

Creating a structured array from flat data that comes from a relational database for example can be quite a hassle.

Suppose you have data like in the following table:

product	country	count
foo	NL	5
foo	US	10
bar	UK	3
bar	DE	2
bar	DE	8

And you want to transform it to an array like the following:

$report = [
    'foo' => [
        'NL' => 5,
        'US' => 10,
    ],
    'bar' => [
        'UK' => 3,
        'DE' => 10,
    ]
];

What you often end up with is code that looks like this:

$report = [];
foreach ($rows as $row) {
    if (!isset($report[$row['product']][$row['country']])) {
        $report[$row['product']][$row['country']] = 0;
    }
    $report[$row['product']][$row['country']] += $row['count'];
}

The isset part takes up 3 lines total and is hard to read. This is where ReportArray comes in. Instead of the above you can do the following:

$storage = new rpkamp\ReportArray\Storage();
$report = new rpkamp\ReportArray\ReportArray($storage);

foreach ($rows as $row) {
    $report->add($row['product'], $row['country'], $row['count']);
}

At any point if you want the array shown above just call $report->get().

That's it. No more isset, just tell the class to add a value and it will assume a value of 0 for any key that was not yet set. If you want a different value than 0 as default value, pass it to the rpkamp\ReportArray\Storage class constructor as an argument.

In addition to the add method, there is also sub for subtraction, mul for multiplication, div for division, pow for powers and root for roots.

Installation

From the command line run:

composer require rpkamp/report-array

Adding methods

You can easily add your own method if you need to by providing it to rpkamp\ReportArray\ReportArray#addMethod.

For example:

$storage = new rpkamp\ReportArray\Storage();
$report = new rpkamp\ReportArray\ReportArray($storage);

$report->addMethod('myCustomMethod', function ($carry, $value) {
    return 2 * $carry + $value;
});

$report->set('foo', 2);
$report->myCustomMethod('foo', 10);
$report->get(); // returns ['foo' => 14] (2 * 2 + 10)