PHP SPL 迭代器

goodmm

　　SPL提供了5个迭代器接口：Traversable.Iterator.IteratorAggregate.OuterIterator ,RecurseiveIterator。  
　　使用IteratorAggregate接口

class MyIterableClass implements IteratorAggregate{
protected $arr;
public function __construct(){
$this->arr=array(1,2,3);
}
public function getIterator(){
return new ArrayIterator($this->arr);
}
}
foreach(new MyIterableClass() as $value){
echo $value."\n";
}
输出如下

使用ArrayIterator迭代器
$arr=array('a','b','c');
$iterator=new ArrayIterator($arr);
foreach($iterator as $val){
echo $val;
}


使用LimitIterator 迭代器
$arr=array(1,2,3,4,5,6,7,8);
$arrIterator=new ArrayIterator($arr);
$limitIterator=new LimitIterator($arrIterator,3,4);
foreach ($limitIterator as $number){
echo $number;
}


使用AppendIterator迭代器
$arrFirst=new ArrayIterator(array(1,2,3));
$arrSecond=new ArrayIterator(array(4,5,6));
$iterator=new AppendIterator();
$iterator->append($arrFirst);
$iterator->append($arrSecond);
foreach($iterator as $number){
echo $number;
}


高级的数组合并功能
$arrFirst=new ArrayIterator(array(1,2,3));
$arrSecond=new ArrayIterator(array(4,5,6));
$iterator=new AppendIterator();
$iterator->append(new LimitIterator($arrFirst,0,2));
$iterator->append(new LimitIterator($arrSecond,0,2));
print_r(iterator_to_array($iterator,false));

　　
　　

使用FilterIterator 迭代器
$arrFirst=new ArrayIterator(array(1,2,3));
$arrSecond=new ArrayIterator(array(4,5,6));
$iterator=new AppendIterator();
$iterator->append(new LimitIterator($arrFirst,0,2));
$iterator->append(new LimitIterator($arrSecond,0,2));
print_r(iterator_to_array($iterator,false));



使用一个基本的RegexIterator迭代器
$arr=array('apple','avocado','orange','pineapple');
$arrIterator=new ArrayIterator($arr);
$iterator=new RegexIterator($arrIterator,'/^a/');
print_r(iterator_to_array($iterator));