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Patrick Florek fa87eca375 Add new class Set for simple Set-theoretical operations

### Features

* Works only with primitive types int, float, string
* Implements set theortic operations union, intersection, complement
* Modifies set by adding, removing elements
* Implements \IteratorAggregate for use in loops

### Implementation details

Based on array functions:
* array_diff,
* array_merge,
* array_intersection,
* array_unique,
* array_values,
* sort.

### Drawbacks

* **Do not work with objects.**
* Power set and Cartesian product returning array of Set

2016-09-10 13:24:43 +02:00

1.8 KiB

Raw Blame History

Set

Class that wraps PHP arrays containing primitive types to mathematical sets.

Creation

To create Set use flat arrays containing primitives only:

use \Phpml\Math\Set;

$set = new Set([1, 2, 2, 3, 1.1, -1, -10]);
$set->toArray();
// return [-10, -1, 1, 1.1, 2, 3]

$set = new Set(['B', '', 'A']);
$set->toArray();
// return ['', 'A', 'B']

Injected array is sorted by SORT_ASC, duplicates are removed and index is rewritten.

Union

Create the union of two Sets:

use \Phpml\Math\Set;

$union = Set::union(new Set([1, 3]), new Set([1, 2]));
$union->toArray();
//return [1, 2, 3]

Intersection

Create the intersection of two Sets:

use \Phpml\Math\Set;

$intersection = Set::intersection(new Set(['A', 'C']), new Set(['B', 'C']));
$intersection->toArray();
//return ['C']

Complement

Create the set-theoretic difference of two Sets:

use \Phpml\Math\Set;

$difference = Set::difference(new Set(['A', 'B', 'C']), new Set(['A']));
$union->toArray();
//return ['B', 'C']

Adding elements

use \Phpml\Math\Set;

$set = new Set([1, 2]);
$set->addAll([3]);
$set->add(4);
$set->toArray();
//return [1, 2, 3, 4]

Removing elements

use \Phpml\Math\Set;

$set = new Set([1, 2]);
$set->removeAll([2]);
$set->remove(1);
$set->toArray();
//return []

Check membership

use \Phpml\Math\Set;

$set = new Set([1, 2]);
$set->containsAll([2, 3]);
//return false
$set->contains(1);
//return true

Cardinality

use \Phpml\Math\Set;

$set = new Set([1, 2]);
$set->cardinality();
//return 2

Is empty

use \Phpml\Math\Set;

$set = new Set();
$set->isEmpty();
//return true

Working with loops

use \Phpml\Math\Set;

$set = new Set(['A', 'B', 'C']);

foreach($set as $element) {
    echo "$element, ";
}

// echoes A, B, C

1.8 KiB Raw Blame History

Set