Iterators
PHP Manual

The LimitIterator class

简介

The LimitIterator class allows iteration over a limited subset of items in an Iterator.

类摘要

LimitIterator extends IteratorIterator implements OuterIterator , Traversable , Iterator {
/* 方法 */
__construct ( Iterator $iterator [, int $offset = 0 [, int $count = -1 ]] )
public mixed current ( void )
public Iterator getInnerIterator ( void )
public int getPosition ( void )
public mixed key ( void )
public void next ( void )
public void rewind ( void )
public int seek ( int $position )
public bool valid ( void )
}

范例

Example #1 LimitIterator usage example

<?php

// Create an iterator to be limited
$fruits = new ArrayIterator(array(
    'apple',
    'banana',
    'cherry',
    'damson',
    'elderberry'
));

// Loop over first three fruits only
foreach (new LimitIterator($fruits, 0, 3) as $fruit) {
    var_dump($fruit);
}

echo "\n";

// Loop from third fruit until the end
// Note: offset starts from zero for apple
foreach (new LimitIterator($fruits, 2) as $fruit) {
    var_dump($fruit);
}

?>

以上例程会输出：

string(5) "apple"
string(6) "banana"
string(6) "cherry"

string(6) "cherry"
string(6) "damson"
string(10) "elderberry"

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Iterators
PHP Manual