問題描述

我有一個 foreach 循環，我想查看循環中是否有下一個元素，以便我可以將當??前元素與下一個元素進行比較.我怎樣才能做到這一點?我已經閱讀了 current 和 next 函數，但我不知道如何使用它們.

I have a foreach loop and I want to see if there is a next element in the loop so I can compare the current element with the next. How can I do this? I've read about the current and next functions but I can't figure out how to use them.

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推薦答案

一種獨特的方法是反轉數組和 then 循環.這也適用于非數字索引數組:

A unique approach would be to reverse the array and then loop. This will work for non-numerically indexed arrays as well:

$items = array(
    'one'   => 'two',
    'two'   => 'two',
    'three' => 'three'
);
$backwards = array_reverse($items);
$last_item = NULL;

foreach ($backwards as $current_item) {
    if ($last_item === $current_item) {
        // they match
    }
    $last_item = $current_item;
}

如果您仍然對使用 current 和 next 函數感興趣，您可以這樣做:

If you are still interested in using the current and next functions, you could do this:

$items = array('two', 'two', 'three');
$length = count($items);
for($i = 0; $i < $length - 1; ++$i) {
    if (current($items) === next($items)) {
        // they match
    }
}

#2 可能是最好的解決方案.注意，$i <$length - 1; 將在比較數組中的最后兩項后停止循環.我把它放在循環中，以便在示例中明確.你應該只計算 $length = count($items) - 1;

#2 is probably the best solution. Note, $i < $length - 1; will stop the loop after comparing the last two items in the array. I put this in the loop to be explicit with the example. You should probably just calculate $length = count($items) - 1;

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