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PHP - Manual: LimitIterator

2024-12-23

LimitIterator 类

(PHP 5 >= 5.1.0, PHP 7, PHP 8)

简介

LimitIterator 类允许遍历一个 Iterator 的限定子集的元素。

类摘要

class LimitIterator extends IteratorIterator {
/* 方法 */
public __construct(Iterator $iterator, int $offset = 0, int $limit = -1)
public current(): mixed
public getPosition(): int
public key(): mixed
public next(): void
public rewind(): void
public seek(int $offset): int
public valid(): bool
/* 继承的方法 */
public IteratorIterator::next(): void
}

范例

示例 #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($fruits03) as $fruit) {
    
var_dump($fruit);
}

echo 
"\n";

// Loop from third fruit until the end
// Note: offset starts from zero for apple
foreach (new LimitIterator($fruits2) 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"

目录

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User Contributed Notes 1 note

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christophg at grenz-bonn dot de
11 months ago
If the inner iterator implements SeekableIterator, LimitIterator uses seek() after rewind() to move to the offset.

官方地址:https://www.php.net/manual/en/class.limititerator.php

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