由于 PHP 中没有迭代器，因此在不获取数组长度的情况下循环遍历数组的唯一方法是使用 foreach 循环。

假设我有以下循环:

foreach ($testing_array as $testing_entry) {
    $result = my_testing_api_call($testing_entry);
    if ($result == 'server dead')
        break;
    else if ($result == 'done') {
        // do something to handle success code
        continue;
    }
    else {
        sleep(5);
        // I want to retry my_testing_api_call with current $testing entry, but don't know what to write
    }
}

一种方法是改用 for 循环。

for ( $i=0; $i < count($testing_array); $i++ ) {
    $result = my_testing_api_call($testing_entry[$i]);
    if ($result == 'server dead')
        break;
    else if ($result == 'done') {
        // do something to handle success code
        continue;
    }
    else {
        sleep(5);
        $i--; //so it will repeat the current iteration.
    }
}

问题是 $testing_array 最初并没有使用数字作为索引，所以我必须做一些数据处理才能使用 for 循环。有没有一种方法可以在 foreach 循环中重复特定的迭代？

最佳答案

也许做一段时间对你有用。

未经测试的代码:

foreach ($testing_array as $testing_entry) {
    do {
        $result = my_testing_api_call($testing_entry);
        if ($result == 'server dead') {
            break 2;  // break both loops
        } elseif ($result == 'done') {
            // do something to handle success code
        } else {
            sleep(5);
            // I want to retry my_testing_api_call with current $testing entry, but don't know what to write
        }
    } while ($result !== 'done');
}

或者在迭代时破坏输入数组的单个循环结构。

未经测试的代码:

$result = '';
while ($testing_array && $result !== 'server dead') {
    $result = my_testing_api_call(current($testing_array));
    if ($result == 'done') {
        // do something to handle success code
        array_shift($testing_array);
    } elseif ($result !== 'server dead') {
        sleep(5); // I want to retry my_testing_api_call with current $testing entry, but don't know what to write
    }
}

或者您可以使用您的 for通过索引循环 $test_array与 array_values()如果您不需要 // do something 中的 key .

$testing_array = array_values($testing_array);
for ($i=0, $count=count($testing_array); $i < $count; ++$i) {
    $result = my_testing_api_call($testing_entry[$i]);
    if ($result == 'server dead') {
        break;
    } else if ($result == 'done') {
        // do something to handle success code
    } else {
        sleep(5);
        --$i; //so it will repeat the current iteration.
    }
}

如果你确实需要按键脚本，但你想使用for ，您可以存储一个索引键数组，这将允许您使用 $i访问 key 并保持数据同步。

我的最终建议:

使用 while (key($testing_array) !== null) {...}在不破坏元素的情况下移动指针。

代码:(Demo)

$array1 = [
    "one" => 1,
    "two" => 2,
    "three" => 3,
    "four" => 4
];

while (key($array1)!==null) {  // check if the internal pointer points beyond the end of the elements list or the array is empty
    $current = current($array1);
    $key = key($array1);
    echo "$key => $current\n";         // display current key value pair
    if ($current < 3) {                // an arbitrary condition
        echo "\t";
        $array1[$key] = ++$current;    // increment the current value
    } else {                           // current value is satisfactory
        echo "\t(advance pointer)\n";
        next($array1);                 // move pointer
    }
}

输出:

one => 1
    one => 2
    one => 3
    (advance pointer)
two => 2
    two => 3
    (advance pointer)
three => 3
    (advance pointer)
four => 4
    (advance pointer)

关于php - 如何在 PHP 的 foreach 循环中重复特定的迭代？，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/49103835/