The Iterator interface
(PHP 5, PHP 7, PHP 8)
Introduction
Interface for external iterators or objects that can be iterated themselves internally.
Interface synopsis
Predefined iterators
PHP already provides a number of iterators for many day to day tasks. See SPL iterators for a list.
Examples
Example #1 Basic usage
This example demonstrates in which order methods are called when using foreach with an iterator.
<?php
class myIterator implements Iterator {
private $position = 0;
private $array = array(
"firstelement",
"secondelement",
"lastelement",
);
public function __construct() {
$this->position = 0;
}
public function rewind(): void {
var_dump(__METHOD__);
$this->position = 0;
}
#[\ReturnTypeWillChange]
public function current() {
var_dump(__METHOD__);
return $this->array[$this->position];
}
#[\ReturnTypeWillChange]
public function key() {
var_dump(__METHOD__);
return $this->position;
}
public function next(): void {
var_dump(__METHOD__);
++$this->position;
}
public function valid(): bool {
var_dump(__METHOD__);
return isset($this->array[$this->position]);
}
}
$it = new myIterator;
foreach($it as $key => $value) {
var_dump($key, $value);
echo "\n";
}
?>
The above example will output something similar to:
string(18) "myIterator::rewind" string(17) "myIterator::valid" string(19) "myIterator::current" string(15) "myIterator::key" int(0) string(12) "firstelement" string(16) "myIterator::next" string(17) "myIterator::valid" string(19) "myIterator::current" string(15) "myIterator::key" int(1) string(13) "secondelement" string(16) "myIterator::next" string(17) "myIterator::valid" string(19) "myIterator::current" string(15) "myIterator::key" int(2) string(11) "lastelement" string(16) "myIterator::next" string(17) "myIterator::valid"
See Also
See also object iteration.
Table of Contents
- Iterator::current — Return the current element
- Iterator::key — Return the key of the current element
- Iterator::next — Move forward to next element
- Iterator::rewind — Rewind the Iterator to the first element
- Iterator::valid — Checks if current position is valid