PHP - 使用点表示键将多维数组转换为2D数组

Question

有很多关于使用点表示法访问PHP数组的技巧和代码示例,但我想做一些相反的事情.我想采取像这样的多维数组:

$myArray = array(
    'key1' => 'value1',
    'key2' => array(
        'subkey' => 'subkeyval'
    ),
    'key3' => 'value3',
    'key4' => array(
        'subkey4' => array(
            'subsubkey4' => 'subsubkeyval4',
            'subsubkey5' => 'subsubkeyval5',
        ),
        'subkey5' => 'subkeyval5'
    )
);

把它变成这个(可能通过一些递归函数):

$newArray = array(
    'key1'                    => 'value1',
    'key2.subkey'             => 'subkeyval',
    'key3'                    => 'value3',
    'key4.subkey4.subsubkey4' => 'subsubkeyval4',
    'key4.subkey5.subsubkey5' => 'subsubkeyval5',
    'key4.subkey5'            => 'subkeyval5'
);

Answer 1

代码

$ritit = new RecursiveIteratorIterator(new RecursiveArrayIterator($myArray));
$result = array();
foreach ($ritit as $leafValue) {
    $keys = array();
    foreach (range(0, $ritit->getDepth()) as $depth) {
        $keys[] = $ritit->getSubIterator($depth)->key();
    }
    $result[ join('.', $keys) ] = $leafValue;
}

产量

Array
(
    [key1] => value1
    [key2.subkey] => subkeyval
    [key3] => value3
    [key4.subkey4.subsubkey4] => subsubkeyval4
    [key4.subkey4.subsubkey5] => subsubkeyval5
    [key4.subkey5] => subkeyval5
)

演示:http://codepad.org/YiygqxTM

我需要去,但如果你明天需要解释,请问我.

Answer 2

已经有答案了RecursiveIteratorIterator。但这里有一个更优化的解决方案，避免使用嵌套循环：

$iterator = new RecursiveIteratorIterator(
    new RecursiveArrayIterator($arr),
    RecursiveIteratorIterator::SELF_FIRST
);
$path = [];
$flatArray = [];

foreach ($iterator as $key => $value) {
    $path[$iterator->getDepth()] = $key;

    if (!is_array($value)) {
        $flatArray[
            implode('.', array_slice($path, 0, $iterator->getDepth() + 1))
        ] = $value;
    }
}

这里有几点需要说明。注意这里常量的使用RecursiveIteratorIterator::SELF_FIRST。这很重要，因为默认的密钥RecursiveIteratorIterator::LEAVES_ONLY不会让我们访问所有密钥。因此，通过这个常量集，我们从数组的顶层开始并深入。这种方法让我们可以存储密钥的历史记录，并在使用丰富的叶子方法时准备密钥RecursiveIteratorIterator::getDepth。

这是一个工作演示。

Answer 3

这将处理任意级别的嵌套：

<? //PHP 5.4+
$dotFlatten = static function(array $item, $context = '') use (&$dotFlatten){
    $retval = [];
    foreach($item as $key => $value){
        if (\is_array($value) === true){
            foreach($dotFlatten($value, "$context$key.") as $iKey => $iValue){
                $retval[$iKey] = $iValue;
            }
        } else {
            $retval["$context$key"] = $value;
        }
    }
    return $retval;
};

var_dump(
    $dotFlatten(
        [
            'key1' => 'value1',
            'key2' => [
                'subkey' => 'subkeyval',
            ],
            'key3' => 'value3',
            'key4' => [
                'subkey4' => [
                    'subsubkey4' => 'subsubkeyval4',
                    'subsubkey5' => 'subsubkeyval5',
                ],
                'subkey5' => 'subkeyval5',
            ],
        ]
    )
);
?>