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
)

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
)

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)); 

我刚刚创建了一个ArrayHelper类，它可以使数值索引变得非常容易。

class ArrayHelper
{
    /*
        Inserts a value at the given position or throws an exception if
        the position is out of range.
        This function will push the current values up in index. ex. if 
        you insert at index 1 then the previous value at index 1 will 
        be pushed to index 2 and so on.
        $pos: The position where the inserted value should be placed. 
        Starts at 0.
    */
    public static function insertValueAtPos(array &$array, $pos, $value) {
        $maxIndex = count($array)-1;

        if ($pos === 0) {
            array_unshift($array, $value);
        } elseif (($pos > 0) && ($pos <= $maxIndex)) {
            $firstHalf = array_slice($array, 0, $pos);
            $secondHalf = array_slice($array, $pos);
            $array = array_merge($firstHalf, array($value), $secondHalf);
        } else {
            throw new IndexOutOfBoundsException();
        }

    }
}

例子:

$array = array('a', 'b', 'c', 'd', 'e');
$insertValue = 'insert';
\ArrayHelper::insertValueAtPos($array, 3, $insertValue);

开始$数组:

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

结果:

Array ( 
    [0] => a 
    [1] => b 
    [2] => c 
    [3] => insert 
    [4] => d 
    [5] => e 
)

我这样做

    $slightly_damaged = array_merge(
        array_slice($slightly_damaged, 0, 4, true) + ["4" => "0.0"], 
        array_slice($slightly_damaged, 4, count($slightly_damaged) - 4, true)
    );