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    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::current(): mixed
    public IteratorIterator::getInnerIterator(): ?Iterator
    public IteratorIterator::key(): mixed
    public IteratorIterator::next(): void
    public IteratorIterator::rewind(): void
    public IteratorIterator::valid(): bool
    }

    示例

    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($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);
    }

    ?>

    以上示例会输出：

    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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    0
    christophg at grenz-bonn dot de
    3 years ago
    If the inner iterator implements SeekableIterator, LimitIterator uses seek() after rewind() to move to the offset.
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