代码:

function insertValueAtPosition($arr, $insertedArray, $position) {
    $i = 0;
    $new_array=[];
    foreach ($arr as $key => $value) {
        if ($i == $position) {
            foreach ($insertedArray as $ikey => $ivalue) {
                $new_array[$ikey] = $ivalue;
            }
        }
        $new_array[$key] = $value;
        $i++;
    }
    return $new_array;
}

例子:

$array        = ["A"=8, "K"=>3];
$insert_array = ["D"= 9];

insertValueAtPosition($array, $insert_array, $position=2);
// result ====> ["A"=>8,  "D"=>9,  "K"=>3];

也许看起来不完美，但很有效。

Array_slice()可以用来提取数组的部分，联合数组操作符(+)可以重新组合这些部分。

$res = array_slice($array, 0, 3, true) +
    array("my_key" => "my_value") +
    array_slice($array, 3, count($array)-3, true);

这个例子:

$array = array(
  'zero'  => '0',
  'one'   => '1',
  'two'   => '2',
  'three' => '3',
);
$res = array_slice($array, 0, 3, true) +
    array("my_key" => "my_value") +
    array_slice($array, 3, count($array) - 1, true) ;
print_r($res);

给:

Array
(
    [zero] => 0
    [one] => 1
    [two] => 2
    [my_key] => my_value
    [three] => 3
)

对于第一个数组，使用array_splice():

$array_1 = array(
  '0' => 'zero',
  '1' => 'one',
  '2' => 'two',
  '3' => 'three',
);

array_splice($array_1, 3, 0, 'more');
print_r($array_1);

输出:

Array(
    [0] => zero
    [1] => one
    [2] => two
    [3] => more
    [4] => three
)

对于第二个，没有顺序，所以你只需要做:

$array_2['more'] = '2.5';
print_r($array_2);

把钥匙按你想要的排序。

我需要一些可以在键之前，替换，之后插入的东西;如果没有找到目标键，则在数组的开头或结尾添加。默认是在键后插入。

新功能

/**
 * Insert element into an array at a specific key.
 *
 * @param array $input_array
 *   The original array.
 * @param array $insert
 *   The element that is getting inserted; array(key => value).
 * @param string $target_key
 *   The key name.
 * @param int $location
 *   1 is after, 0 is replace, -1 is before.
 *
 * @return array
 *   The new array with the element merged in.
 */
function insert_into_array_at_key(array $input_array, array $insert, $target_key, $location = 1) {
  $output = array();
  $new_value = reset($insert);
  $new_key = key($insert);
  foreach ($input_array as $key => $value) {
    if ($key === $target_key) {
      // Insert before.
      if ($location == -1) {
        $output[$new_key] = $new_value;
        $output[$key] = $value;
      }
      // Replace.
      if ($location == 0) {
        $output[$new_key] = $new_value;
      }
      // After.
      if ($location == 1) {
        $output[$key] = $value;
        $output[$new_key] = $new_value;
      }
    }
    else {
      // Pick next key if there is an number collision.
      if (is_numeric($key)) {
        while (isset($output[$key])) {
          $key++;
        }
      }
      $output[$key] = $value;
    }
  }
  // Add to array if not found.
  if (!isset($output[$new_key])) {
    // Before everything.
    if ($location == -1) {
      $output = $insert + $output;
    }
    // After everything.
    if ($location == 1) {
      $output[$new_key] = $new_value;
    }

  }
  return $output;
}

输入代码

$array_1 = array(
  '0' => 'zero',
  '1' => 'one',
  '2' => 'two',
  '3' => 'three',
);
$array_2 = array(
  'zero'  => '0',
  'one'   => '1',
  'two'   => '2',
  'three' => '3',
);

$array_1 = insert_into_array_at_key($array_1, array('sample_key' => 'sample_value'), 2, 1);
print_r($array_1);
$array_2 = insert_into_array_at_key($array_2, array('sample_key' => 'sample_value'), 'two', 1);
print_r($array_2);

输出

Array
(
    [0] => zero
    [1] => one
    [2] => two
    [sample_key] => sample_value
    [3] => three
)
Array
(
    [zero] => 0
    [one] => 1
    [two] => 2
    [sample_key] => sample_value
    [three] => 3
)

不像Artefacto的答案那么具体，但基于他使用array_slice()的建议，我写了下一个函数:

function arrayInsert($target, $byKey, $byOffset, $valuesToInsert, $afterKey) {
    if (isset($byKey)) {
        if (is_numeric($byKey)) $byKey = (int)floor($byKey);
        $offset = 0;

        foreach ($target as $key => $value) {
            if ($key === $byKey) break;
            $offset++;
        }

        if ($afterKey) $offset++;
    } else {
        $offset = $byOffset;
    }

    $targetLength = count($target);
    $targetA = array_slice($target, 0, $offset, true);
    $targetB = array_slice($target, $offset, $targetLength, true);
    return array_merge($targetA, $valuesToInsert, $targetB);
}

特点:

插入一个或múltiple值 插入键值对 在键前/键后插入，或按偏移量插入

使用例子:

$target = [
    'banana' => 12,
    'potatoe' => 6,
    'watermelon' => 8,
    'apple' => 7,
    2 => 21,
    'pear' => 6
];

// Values must be nested in an array
$insertValues = [
    'orange' => 0,
    'lemon' => 3,
    3
];

// By key
// Third parameter is not applicable
//     Insert after 2 (before 'pear')
var_dump(arrayInsert($target, 2, null, $valuesToInsert, true));
//     Insert before 'watermelon'
var_dump(arrayInsert($target, 'watermelon', null, $valuesToInsert, false)); 

// By offset
// Second and last parameter are not applicable
//     Insert in position 2 (zero based i.e. before 'watermelon')
var_dump(arrayInsert($target, null, 2, $valuesToInsert, null)); 

最简单的解决方案，如果你想在某个键后插入(一个元素或数组):

function array_splice_after_key($array, $key, $array_to_insert)
{
    $key_pos = array_search($key, array_keys($array));
    if($key_pos !== false){
        $key_pos++;
        $second_array = array_splice($array, $key_pos);
        $array = array_merge($array, $array_to_insert, $second_array);
    }
    return $array;
}

如果你有:

$array = [
    'one' => 1,
    'three' => 3
];
$array_to_insert = ['two' => 2];

和执行:

$result_array = array_splice_after_key($array, 'one', $array_to_insert);

你会有:

Array ( 
    ['one'] => 1 
    ['two'] => 2 
    ['three'] => 3 
)