ArrayComparator

Array comparison helper.

Principle

Here is the default behavior:

Array 1	Array 2	Method called
foo => Foo	foo => Foo	whenEqual
bar => Bar	bar => Foo	whenDifferent
baz => Baz		whenMissingRight
	bam => Bam	whenMissingLeft

By default, array keys are compared. This behavior can be customized.

Usage

$comparator = new ArrayComparator();

$comparator->whenEqual(function ($item1, $item2) {
    // Do your stuff !
})
->whenDifferent(function ($item1, $item2) {
    // Do your stuff !
})
->whenMissingRight(function ($item1) {
    // Do your stuff !
})
->whenMissingLeft(function ($item2) {
    // Do your stuff !
});

$comparator->compare($array1, $array2);

Advanced example for Doctrine entities for example:

$comparator = new ArrayComparator();

// Set that items are considered the same if they have the same id
// Array keys are ignored in this example
$comparator->setItemIdentityComparator(function ($key1, $key2, $item1, $item2) {
    return $item1->id === $item2->id;
});

// Items have differences if their name differ
$comparator->setItemComparator(function ($item1, $item2) {
    return $item1->name === $item2->name;
});

$comparator->whenEqual(function ($item1, $item2) {
    // Do your stuff !
})
->whenDifferent(function ($item1, $item2) {
    // Do your stuff !
})
->whenMissingRight(function ($item1) {
    // Do your stuff !
})
->whenMissingLeft(function ($item2) {
    // Do your stuff !
});

$comparator->compare($array1, $array2);

Note that you can also use any PHP callable format instead of inline functions, for example:

$comparator->whenDifferent(array($this, 'whenDifferent'));

Documentation

• whenEqual - Called when 2 items are found in both arrays, and are equal

$comparator->whenEqual(function ($item1, $item2) {
});

• whenDifferent - Called when 2 items are found in both arrays, but are different

$comparator->whenDifferent(function ($item1, $item2) {
});

• whenMissingRight - Called when an item is in the first array (left array) but not in the second (right array)

$comparator->whenMissingRight(function ($item1) {
});

• whenMissingLeft - Called when an item is in the second array (right array) but not in the first (left array)

$comparator->whenMissingLeft(function ($item2) {
});

• setItemIdentityComparator - Overrides the default identity comparator which determine if 2 items represent the same thing

Can be used for example to compare the id of the items.

The default behavior compares the array keys using ===.

$comparator->setItemIdentityComparator(function ($key1, $key2, $item1, $item2) {
    // return true or false
});

• setItemComparator - Overrides the default item comparator to determine if 2 items (representing the same thing) have differences

Can be used for example to compare specific attributes of the items. The function should return "is equal", i.e. true if items have no differences (then nothing is done because all is good), or false if they have differences (then whenDifferent is called).

The default behavior compares the items using ==.

$comparator->setItemComparator(function ($item1, $item2) {
    // return true or false
});

Custom comparator

There is an alternative to using setItemIdentityComparator and setItemComparator by writing your own comparator class:

class CustomComparator extends ArrayComparator
{
    protected function areSame($key1, $key2, $item1, $item2)
    {
        // Your stuff
        return $item1->id === $item2->id;
    }

    protected function areEqual($item1, $item2)
    {
        // Your stuff
        return $item1->name === $item2->name;
    }
}

Installation

Edit your composer.json to add the dependency:

{
	"require": {
		"myclabs/array-comparator": "1.0.*"
	}
}

ArrayComparator is tested with PHP 5.3 and greater.

Changelog

• 1.0: Stable version after testing and use in production (no change from 0.3)
• 0.3: PHP 5.3 compatibility and support all PHP callable types
• 0.2: Allowed to extend the ArrayComparator class and write custom comparators
• 0.1: First version

Contribute

Install dependencies with Composer:

composer install

TODO:

• Optimize the array traversals
• Improve documentation ?