92 lines
4.0 KiB
Markdown
92 lines
4.0 KiB
Markdown
# ext-collections
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[](https://travis-ci.com/CismonX/ext-collections)
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[](https://codecov.io/gh/CismonX/ext-collections)
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[](LICENSE)
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## 1. Introduction
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This PHP extension provides a set of useful and convenient operations on PHP arrays, which makes working with arrays simple and scalable.
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Method names and functionalities are inspired by [Kotlin.Collections](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin.collections/), having a slightly different style than that of [Laravel Collections](https://laravel.com/docs/5.8/collections).
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Requires PHP version >= 7.1 and < 8.0 (master branch).
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### 1.1 Example
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Here is a simple example on how to work with arrays gracefully using this extension.
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```php
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$employees = [
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['name' => 'Alice', 'gender' => 'female', 'age' => 35],
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['name' => 'Bob', 'gender' => 'male', 'age' => 29],
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['name' => 'David', 'gender' => 'male', 'age' => 40],
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['name' => 'Benjamin', 'gender' => 'male', 'age' => 32]
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];
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// Trying to get an array of names of male employees,
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// sorted by the descending order of their age.
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$names = Collection::init($employees)
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->filter(function ($value) {
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return $value['gender'] == 'male';
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})
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->sortedByDescending(function ($value) {
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return $value['age'];
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})
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->map(function ($value) {
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return $value['name'];
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})
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->toArray();
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// You got $names == ['David', 'Benjamin', 'Bob'].
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```
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## 2. Getting Started
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### 2.1 Installation
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Like other PHP extensions, ext-collections can be built and installed with a few commands:
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```bash
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phpize
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./configure
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make
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sudo make install
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```
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Include it in your PHP configuration file to enable this extension:
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```php.ini
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extension=collections.so
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```
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Building on Windows is not as convenient, however, pre-built binaries for Windows are provided in the [releases](https://github.com/CismonX/ext-collections/releases). If you want to build it yourself, follow the [official PHP wiki](https://wiki.php.net/internals/windows/stepbystepbuild_sdk_2).
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### 2.2 API Reference
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See [stubs](stubs/) directory for signatures of all classes and methods of this extension, with PHPDoc. They can also serve as IDE helper.
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### 2.3 PHP-style Access
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The `Collection` class implements `ArrayAccess` and `Countable` interface internally, you can treat an instance of `Collection` as an `ArrayObject`.
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* The `isset()`, `unset()` keywords can be used on elements of `Collection`.
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* Elements can be accessed via property or bracket expression.
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* `empty()`, `count()` can be used on instance of `Collection`.
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* Elements can be traversed via `foreach()` keyword.
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## 3. Notes
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* The `Collection::xxxTo()` methods will preserve the original key-value pairs of destination `Collection` when keys collide.
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* Some methods of `Collection` involves comparing two of its elements, which accepts `$flags` as one of its arguments. When these methods are being invoked, make sure all elements are of the same type (numeric/string/others), otherwise you're likely to get a segfault.
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### 3.1 Copy-on-write Mechanism
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Class `Collection` does not introduce new data structures internally. Instead, it only holds a pointer to a `zend_array`, and all its methods works directly on top of `zend_array`. Which means conversion between `Collection` and `array` does not involve copying, until write operation is performed on one of the duplicates.
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```php
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$foo = ['a', 'b']; // arr0: refcount = 1
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$bar = Collection::init($foo); // arr0: refcount = 2, no copying of either `zend_array` or its elements
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echo $bar->containsValue('a'); // arr0: refcount = 2, read operation, no copying
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$bar->shuffle(); // arr0: refcount = 1, arr1: refcount = 1, write operation, `zend_array` is separated
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$baz = $bar->toArray(); // arr0: refcount = 1, arr1: refcount = 2, no copying
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```
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