README

A PHP library for comparing multi-dimensional arrays and detecting differences.

Features

• Deep comparison of multi-dimensional arrays
• Detects added, removed, and modified values
• Maintains array structure in the result
• Special handling for float comparison with epsilon
• Flatten results into a single-dimensional array with path keys

Installation

Install via Composer:

composer require xpaw/compare-arrays

Usage

Basic Comparison

use xPaw\CompareArrays\CompareArrays;

$oldArray = [
	'user' => [
		'name' => 'John',
		'age' => 30,
		'settings' => [
			'darkMode' => true,
			'notifications' => true
		]
	]
];

$newArray = [
	'user' => [
		'name' => 'John Doe',
		'age' => 30,
		'settings' => [
			'darkMode' => true,
			'notifications' => false
		],
		'lastLogin' => '2025-03-20'
	]
];

$differences = CompareArrays::Diff($oldArray, $newArray);
print_r($differences);

Result:

Array(
    [user] => Array(
		[name] => xPaw\CompareArrays\ComparedValue Object(
			[OldValue] => John
			[NewValue] => John Doe
			[Type] => modified
		)

		[settings] => Array(
			[notifications] => xPaw\CompareArrays\ComparedValue Object(
				[OldValue] => 1
				[NewValue] =>
				[Type] => modified
			)
		)

		[lastLogin] => xPaw\CompareArrays\ComparedValue Object(
			[OldValue] =>
			[NewValue] => 2025-03-20
			[Type] => added
		)
	)
)

Flattening Results

To simplify handling of nested differences, you can flatten the result:

$flattened = CompareArrays::Flatten($differences);
print_r($flattened);

Result:

Array(
    [user/name] => xPaw\CompareArrays\ComparedValue Object(
		[OldValue] => John
		[NewValue] => John Doe
		[Type] => modified
	)

    [user/settings/notifications] => xPaw\CompareArrays\ComparedValue Object(
		[OldValue] => 1
		[NewValue] =>
		[Type] => modified
	)

    [user/lastLogin] => xPaw\CompareArrays\ComparedValue Object(
		[OldValue] =>
		[NewValue] => 2025-03-20
		[Type] => added
	)
)

Custom Separator and Path Prefix

You can customize the separator and add a path prefix when flattening:

// Using a dot as separator
$flattened = CompareArrays::Flatten($differences, '.');

Result:

Array
(
    [user.name] => xPaw\CompareArrays\ComparedValue Object(...)
    [user.settings.notifications] => xPaw\CompareArrays\ComparedValue Object(...)
    [user.lastLogin] => xPaw\CompareArrays\ComparedValue Object(...)
)

API Reference

CompareArrays::Diff(array $Old, array $New): array

Compares two arrays and produces a new array of changes between these arrays.

• The result maintains the same structure as the input arrays
• The deepest values are ComparedValue objects
• Float values are compared with PHP_FLOAT_EPSILON for precision
• Special handling for arrays vs non-arrays in corresponding positions

CompareArrays::Flatten(array $Input, string $Separator = '/', ?string $Path = null): array

Flattens a multi-dimensional array into a one-dimensional array.

• Keys are transformed into paths separated by the specified separator
• Optionally prepend a path prefix to all keys

ComparedValue

Each detected difference is represented by a ComparedValue object with:

• $Type: One of added, removed, or modified
• $OldValue: The value from the old array (null for added items)
• $NewValue: The value from the new array (null for removed items)

Special Cases

Float Comparison

Floating-point values are compared with PHP_FLOAT_EPSILON to handle precision issues:

$differences = CompareArrays::Diff(
	['value' => 0.1],
	['value' => 0.1 + 0.00000001]
);
// Result: empty array (no differences)

$differences = CompareArrays::Diff(
	['value' => 0.1],
	['value' => 0.1 + 0.0001]
);
// Result: detects difference

License

This library is licensed under the MIT License.