The FilterIterator class

(PHP 5 >= 5.1.0, PHP 7, PHP 8)

Introduction

This abstract iterator filters out unwanted values. This class should be extended to implement custom iterator filters. The FilterIterator::accept() must be implemented in the subclass.

Class synopsis

abstract class FilterIterator extends IteratorIterator {

/* Methods */

public __construct(Iterator $iterator)

public accept(): bool

public current(): mixed

public key(): mixed

public next(): void

public rewind(): void

public valid(): bool

/* Inherited methods */

public IteratorIterator::current(): mixed

public IteratorIterator::getInnerIterator(): ?Iterator

public IteratorIterator::key(): mixed

public IteratorIterator::next(): void

public IteratorIterator::rewind(): void

public IteratorIterator::valid(): bool

}

FilterIterator::accept — Check whether the current element of the iterator is acceptable
FilterIterator::__construct — Construct a filterIterator
FilterIterator::current — Get the current element value
FilterIterator::key — Get the current key
FilterIterator::next — Move the iterator forward
FilterIterator::rewind — Rewind the iterator
FilterIterator::valid — Check whether the current element is valid

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User Contributed Notes 3 notes

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Venelin Vulkov ¶

16 years ago


The code below is a simple example of usage . Note that the method which does the actual job is accept. 

<?php
class UserFilter extends FilterIterator 
{
    private $userFilter;
    
    public function __construct(Iterator $iterator , $filter )
    {
        parent::__construct($iterator);
        $this->userFilter = $filter;
    }
    
    public function accept()
    {
        $user = $this->getInnerIterator()->current();
        if( strcasecmp($user['name'],$this->userFilter) == 0) {
            return false;
        }        
        return true;
    }
}

$array = array(
array('name' => 'Jonathan','id' => '5'),
array('name' => 'Abdul' ,'id' => '22')
);

$object = new ArrayObject($array);

// Note it is case insensitive check in our example due the usage of strcasecmp function
$iterator = new UserFilter($object->getIterator(),'abdul');

foreach ($iterator as $result) {
    echo $result['name'];
}

/* Outputs Jonathan */

?>
Regards.

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Anonymous ¶

10 years ago


A little test about the function call order:

<?php

class TestIterator extends IteratorIterator
{
    public function key()
    {
        echo  __FUNCTION__, PHP_EOL;
        return parent::key();
    }

    public function next()
    {
        echo  __FUNCTION__, PHP_EOL;
        return parent::next();
    }

    public function rewind()
    {
        echo  __FUNCTION__, PHP_EOL;
        return parent::rewind();
    }

    public function valid()
    {
        echo  __FUNCTION__, PHP_EOL;
        return parent::valid();
    }
}

class TestFilterIterator extends FilterIterator
{
    public function accept()
    {
        echo  __FUNCTION__, PHP_EOL;
        return true;
    }
}

$iterator = new ArrayIterator(array('a', 'b', 'c'));

foreach (new TestFilterIterator(new TestIterator($iterator)) as $k => $v) {
    echo PHP_EOL;
}

?>

This will output the following:

rewind
valid
key
accept

next
valid
key
accept

next
valid
key
accept

next
valid

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Anonymous ¶

2 years ago


Filter object collection by method:
<?php
/**
  * @method object current()
  */
class CollectionFilterIterator extends FilterIterator
{
     private $methodName;
     private $methodArguments;

     public function function __construct(Iterator $collection, string $methodName, array $methodArguments = [])
     {
             parent::__construct($collection);
             $this->methodName = $methodName;
             $this->methodArguments = array_values($methodArguments);
     }

     public function accept(): bool
     {
             return (bool) $this->current()->{$this->methodName}(...$this->methodArguments);
             // or call_user_func_array([$this->current(), $this->methodName], $this->methodArguments);
     }
}
?>

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The FilterIterator class

Introduction

Class synopsis

Table of Contents

User Contributed Notes 3 notes