取消多维数组中的行设置

Question

我有这个数组$输出，看起来像这样:

Array(
    [0] => Array(
        [0] => 1a
        [1] => 1b
        [2] => 1c
    )
    [1] => Array(
        [0] => 2a
        [1] => 2b
        [2] => 2c
    )
    [2] => Array(
        [0] => 3a
        [1] => 3b
        [2] => 3c
    )
    [3] => Array(
        [0] => 4a
        [1] => 4b
        [2] => 4c
    )
)

等等…

当我想删除第二个元素时，我只需使用:

$output = unset($output[1]);

获取以下内容:

Array(
    [0] => Array(
        [0] => 1a
        [1] => 1b
        [2] => 1c
    )
    [1] => Array(
        [0] => 3a
        [1] => 3b
        [2] => 3c
    )
    [2] => Array(
        [0] => 4a
        [1] => 4b
        [2] => 4c
    )
)

我的问题是如何删除数组中每个元素的每第二个元素([0][1]，[1][1]，[2][1]，[3][1]，…)，以获得以下内容:

Array(
    [0] => Array(
        [0] => 1a
        [1] => 1c
    )
    [1] => Array(
        [0] => 2a
        [1] => 2c
    )
    [2] => Array(
        [0] => 3a
        [1] => 3c
    )
    [3] => Array(
        [0] => 4a
        [1] => 4c
    )
)

Answer 1

不能用一个简单的命令完成，但是你可以使用一个循环:

foreach(array_keys($output) as $key) {
   unset($output[$key][1]);
}

Answer 2

干净整洁:

$f = function(&$a,$k) { unset($a[1]); };
array_walk($arr, $f);

或:

array_walk($arr, function (&$a, $k) {
  unset($a[1]); 
});

Answer 3

您可以遍历数组，并在每个子数组中使用您想要的unset():

foreach($output as &$item) {
    unset($item[2]);
}
unset($item); // unset reference

Answer 4

您将使用array_map和array_splice的组合:

function removeSecond( array &$arr )
{
    array_splice( $arr, 1, 1 );
}
$out = array_map( 'removeSecond', $input );

unset的问题是它将使索引保持原样:

$ php -r '$arr = array(array(0,1,2)); unset($arr[0][1]); var_dump($arr);'
array(1) {
  [0]=>
  array(2) {
    [0]=>
    int(0)
    [2]=>
    int(2)
  }
}

当splice将更新索引时:

$ php -r '$arr = array(array(0,1,2)); array_splice($arr[0], 1, 1); var_dump($arr);'
array(1) {
  [0]=>
  array(2) {
    [0]=>
    int(0)
    [1]=>
    int(2)
  }
}

Answer 5

foreach($array as $key=>$val){ unset($val[1]); }

Answer 6

我用这个:

public function array_unset_key_in_children($array, $keyToUnsetInChildren)
{ 
    $newArray = [];
    foreach($array as $key=>$subArray) { 
        unset($subArray[$keyToUnsetInChild]);
        $newArray[$key] = $subArray;
    }
    return $newArray;
}