ashleydawson/canonically-flatten-tree

Pure function to flatten a tree (n-dimensional array) into a canonicalised list array

1.0.2 2019-04-17 09:54 UTC

Requires

• php: ^7.1

Requires (Dev)

• phpunit/phpunit: ^7.5

proprietary

README

Pure PHP function to flatten an n-dimensional tree of scalars (represented as an array) into a single dimension list (also represented as an array).

TODO

• Benchmark various flattening algorithms, including \RecursiveArrayIterator, etc.
• Technically I think it's a nested set we're operating on (sort of), so in v2 I'd propose changing the terminology to suit

Requirements

This function requires PHP >= 7.1

Installation

Installation via Composer:

$ composer req ashleydawson/canonically-flatten-tree

Usage

Basic usage of the function is as follows:

<?php

require 'vendor/autoload.php';

$tree = [
    "gamma", 
    [
        "alpha", 
        [
            "beta",
        ],
    ], 
    [
        [
            [
                "delta",
            ]
        ]
    ],
];

$list = \AshleyDawson\CanonicallyFlattenTree\canonically_flatten_scalar_tree($tree);

print_r($list);

/*
Where output is:

Array
(
    [0] => alpha
    [1] => beta
    [2] => delta
    [3] => gamma
)
*/

Add type checking for scalars:

<?php

require 'vendor/autoload.php';

// This will produce an invalid argument exception stating the nature of the type failure and at what level
// In this case we're asserting that all tree nodes must be of type "string"
try {
    \AshleyDawson\CanonicallyFlattenTree\canonically_flatten_scalar_tree(['alpha', [8]], 'string');
} catch (\InvalidArgumentException $e) {
    var_dump($e);
}

Test & Benchmark

Test with PHPUnit:

$ vendor/bin/phpunit -c .

Benchmark with Blackfire:

$ blackfire run php vendor/bin/phpunit 

There is an example benchmark report available.