Ginq
Array handling in PHP? Be happy with Ginq!
Ginq is a DSL that can handle arrays and iterators of PHP unified., (*1)
Ginq is inspired by Linq to Object, but is not a clone., (*2)
Many functions in Ginq are evaluated in lazy, and no actions are taken until that time. This features bring you many benefits., (*3)
Install
composer.json:, (*4)
{
"require": {
"ginq/ginq": "dev-master"
}
}
see: https://packagist.org/packages/ginq/ginq, (*5)
Usage
$xs = Ginq::from(array(1,2,3,4,5,6,7,8,9,10))
->where(function($x) { return $x % 2 != 0; })
->select(function($x) { return $x * $x; });
;
You pass Ginq data and build a query with it. In this example above, you order Ginq to choose even numbers and square each of them., (*6)
But Ginq do nothing, Ginq knows only you want a result of chosen and squared numbers., (*7)
Let's execute foreach loop with Ginq to get the result., (*8)
foreach ($xs as $x) { echo "$x "; }
The result is, (*9)
1 9 25 49 81
You got the expected result!, (*10)
Next, you can get an array with toList., (*11)
$xs->toList();
```
array(1,9,25,49,81);, (*12)
**Ginq** has functions, well-known in SQL, such as `join()`, `orderBy()`, and `groupBy()` other than `select()`, `where()` listed above.
## Selector and Predicate
Most of methods in **Ginq** receive a closure as a argument.
You may not be familiar with closures, but it is very simple things.
There are just three types of closures in **Ginq**, you can remember simply.
These are predicate, selector, and connection selector.
### Predicate
A closure that passed to a method that do select, such as `where()` is called **predicate**.
Predicate is a closure that receive a pair of key and values in the elements and return boolean value.
```php
function ($v, [$k]) { return $v % 2 == 0; }
You get even numbers when you pass this closure to where().
You can skip second argument when you don't need it in the process., (*13)
Selector
A closure that passed to a method that do projection, such as select() is called selector., (*14)
Selector is a closure that receive a pair of key and value in the elements and create a new value or key, and then return it., (*15)
function ($v, [$k]) { return $v * $v ; }
You get squared numbers of original when you pass this closure to select()., (*16)
This function is used to specify the key of grouping with groupBy(), the key of sorting with groupBy()., (*17)
Connection Selector
Connection Selector is one of the selector that combine two elements into one, is used with join(), zip()., (*18)
function ($v0, $v1, [$k0, $k1]) { return array($v0, $v1) ; }
This function receive 4 arguments, two values and two keys, and then create new value or key and return it.
You can skip arguments when you don't need it in the process., (*19)
These are zip() example that combine each elements from two arrays., (*20)
$foods = array("meat", "pasta", "salada");
$spices = array("time", "basil", "dill");
$xs = Ginq::from($foods)
->zip($spices, function($f, $s) {
return "$f with $s!";
})
;
foreach ($xs as $x) { echo "$x\n"; }
meat with time!
pasta with basil!
salada with dill!
Shortcuts of predicate and selector
Selector can receive a character string instead of a closure., (*21)
They return the value of the field when the element is an object, or return the value of the key when it is an array., (*22)
So,, (*23)
Ginq::from($xs)->select('[key].property');
The example above is same as two examples below., (*24)
Ginq::from($xs)->select(
function ($v, $k) { return $v['key'].property; }
);
see: Property Access (Symfony)
http://symfony.com/doc/current/components/property_access/index.html, (*25)
More complex examples
References
Development
PreRequirements
-
Docker installed.
-
Docker Compose installed.
How to start development (Run test)
- cd docker
- docker-compose up -d
- docker-compose exec php ash
- (in php container)
- composer install
- vendor/bin/phpunit
Note
Wallogit.com
