PHP瀵硅薄杩唬
瀵硅薄杩唬,PHP5鎻愪緵浜嗕竴绉嶈凯浠ｏ紙iteration锛夊璞＄殑鍔熻兘锛屽氨鍍忎娇鐢ㄦ暟缁勯偅鏍凤紝鍙互閫氳繃foreach 鏉ラ亶鍘嗗璞′腑鐨勫睘鎬с傞粯璁ゆ儏鍐典笅锛屽湪澶栭儴杩唬鍙兘寰楀埌澶栭儴鍙鐨勫睘鎬х殑鍊笺
瀵硅薄杩唬
PHP 5 provides a way for objects to be defined so it is possible to iterate through a list of items, with, for example a foreach statement. By default, all visible properties will be used for the iteration. PHP5鎻愪緵浜嗕竴绉嶈凯浠ｏ紙iteration锛夊璞＄殑鍔熻兘锛屽氨鍍忎娇鐢ㄦ暟缁勯偅鏍凤紝鍙互閫氳繃foreach 鏉ラ亶鍘嗗璞′腑鐨勫睘鎬с傞粯璁ゆ儏鍐典笅锛屽湪澶栭儴杩唬鍙兘寰楀埌澶栭儴鍙鐨勫睘鎬х殑鍊笺Example #1 绠鍗曠殑瀵硅薄杩唬
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<code><?php
class MyClass
{
public $var1 = 'value 1';
public $var2 = 'value 2';
public $var3 = 'value 3';
protected $protected = 'protected var';
private $private = 'private var';
function iterateVisible() {
echo "MyClass::iterateVisible: ";
foreach($this as $key => $value) {
print "$key => $value ";
}
}
}
$class = new MyClass();
foreach($class as $key => $value) {
print "$key => $value ";
}
echo " ";
$class->iterateVisible();
?></code>
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浠ヤ笂渚嬬▼浼氳緭鍑猴細
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var1 => value 1
var2 => value 2
var3 => value 3
MyClass::iterateVisible:
var1 => value 1
var2 => value 2
var3 => value 3
protected => protected var
private => private var
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濡備笂鎵绀,the foreach 閬嶅巻浜嗘墍鏈 鍙鐨 灞炴. 浣犱篃鍙互閫氳繃瀹炵幇PHP 5鑷甫鐨 Iterator鎺ュ彛鏉ュ疄鐜拌凯浠. 浣跨敤Iterator鎺ュ彛鍙互璁╁璞¤嚜琛屽喅瀹氬浣曡凯浠ｈ嚜宸层
Example #2 瀹炵幇Iterator鎺ュ彛鐨勮凯浠
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<code><?php
class MyIterator implements Iterator
{
private $var = array();
public function __construct($array)
{
if (is_array($array)) {
$this->var = $array;
}
}
public function rewind() {
echo "rewinding ";
reset($this->var);
}
public function current() {
$var = current($this->var);
echo "current: $var ";
return $var;
}
public function key() {
$var = key($this->var);
echo "key: $var ";
return $var;
}
public function next() {
$var = next($this->var);
echo "next: $var ";
return $var;
}
public function valid() {
$var = $this->current() !== false;
echo "valid: {$var} ";
return $var;
}
}
$values = array(1,2,3);
$it = new MyIterator($values);
foreach ($it as $a => $b) {
print "$a: $b ";
}
?></code>
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浠ヤ笂渚嬬▼浼氳緭鍑猴細
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rewinding
current: 1
valid: 1
current: 1
key: 0
0: 1
next: 2
current: 2
valid: 1
current: 2
key: 1
1: 2
next: 3
current: 3
valid: 1
current: 3
key: 2
2: 3
next:
current:
valid:
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浣犱篃鍙互璁╃被瀹炵幇IteratorAggregate鎺ュ彛锛岃繖鏍蜂綘鐨勭被灏变笉鐢ㄥ己鍒舵у湴瀹炵幇 Iterator鎺ュ彛涓殑鎵鏈夋柟娉曘
Example #3 閫氳繃IteratorAggregate鏉ュ疄鐜板璞¤凯浠
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<code><?php
class MyCollection implements IteratorAggregate
{
private $items = array();
private $count = 0;
// Required definition of interface IteratorAggregate
public function getIterator() {
return new MyIterator($this->items);
}
public function add($value) {
$this->items[$this->count++] = $value;
}
}
$coll = new MyCollection();
$coll->add('value 1');
$coll->add('value 2');
$coll->add('value 3');
foreach ($coll as $key => $val) {
echo "key/value: [$key -> $val] ";
}
?></code>
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浠ヤ笂渚嬬▼浼氳緭鍑猴細
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rewinding
current: value 1
valid: 1
current: value 1
key: 0
key/value: [0 -> value 1]
next: value 2
current: value 2
valid: 1
current: value 2
key: 1
key/value: [1 -> value 2]
next: value 3
current: value 3
valid: 1
current: value 3
key: 2
key/value: [2 -> value 3]
next:
current:
valid:
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浠ヤ笂灏辨槸PHP瀵硅薄杩唬鐨勮缁嗗唴瀹癸紝鏇村淇℃伅璇峰叧娉∣D浜戝叾瀹冪浉鍏虫枃绔狅紒
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