Detailed explanation of PHP iterators and how to use iteration-PHP Tutorial-php.cn

This time I will bring you a detailed explanation of PHP iterators and how to use iterations. What are theprecautionswhen using PHP iterators and iterations? Here are practical cases, let’s take a look.

PHP'sObject-orientedengine provides a very smart feature, that is, you can use theforeach()method to take out all the properties of an object through a loop. Like the array method, the code is as follows:

class Myclass{ public $a = 'php'; public $b = 'onethink'; public $c = 'thinkphp'; } $myclass = new Myclass(); //用foreach()将对象的属性循环出来 foreach($myclass as $key.'=>'.$val){ echo '$'.$key.' = '.$val."
"; } /*返回 $a = php $b = onethink $c = thinkphp */

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If you need to implement more complex behavior, you can achieve it through aniterator(iterator)

//迭代器接口 interface MyIterator{ //函数将内部指针设置回数据开始处 function rewind(); //函数将判断数据指针的当前位置是否还存在更多数据 function valid(); //函数将返回数据指针的值 function key(); //函数将返回将返回当前数据指针的值 function value(); //函数在数据中移动数据指针的位置 function next(); } //迭代器类 class ObjectIterator implements MyIterator{ private $obj;//对象 private $count;//数据元素的数量 private $current;//当前指针 function construct($obj){ $this->obj = $obj; $this->count = count($this->obj->data); } function rewind(){ $this->current = 0; } function valid(){ return $this->current < $this->count; } function key(){ return $this->current; } function value(){ return $this->obj->data[$this->current]; } function next(){ $this->current++; } } interface MyAggregate{ //获取迭代器 function getIterator(); } class MyObject implements MyAggregate{ public $data = array(); function construct($in){ $this->data = $in; } function getIterator(){ return new ObjectIterator($this); } } //迭代器的用法 $arr = array(2,4,6,8,10); $myobject = new MyObject($arr); $myiterator = $myobject->getIterator(); for($myiterator->rewind();$myiterator->valid();$myiterator->next()){ $key = $myiterator->key(); $value = $myiterator->value(); echo $key.'=>'.$value; echo "
"; } /*返回 0=>2 1=>4 2=>6 3=>8 4=>10 */

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I believe you have read this article You have mastered the case method. For more exciting information, please pay attention to other related articles on the PHP Chinese website!