该函数支持:

数字键和关联键 在建立键之前或之后插入 如果key未建立，则附加到数组末尾

function insert_into_array( $array, $search_key, $insert_key, $insert_value, $insert_after_founded_key = true, $append_if_not_found = false ) {

        $new_array = array();

        foreach( $array as $key => $value ){

            // INSERT BEFORE THE CURRENT KEY? 
            // ONLY IF CURRENT KEY IS THE KEY WE ARE SEARCHING FOR, AND WE WANT TO INSERT BEFORE THAT FOUNDED KEY
            if( $key === $search_key && ! $insert_after_founded_key )
                $new_array[ $insert_key ] = $insert_value;

            // COPY THE CURRENT KEY/VALUE FROM OLD ARRAY TO A NEW ARRAY
            $new_array[ $key ] = $value;

            // INSERT AFTER THE CURRENT KEY? 
            // ONLY IF CURRENT KEY IS THE KEY WE ARE SEARCHING FOR, AND WE WANT TO INSERT AFTER THAT FOUNDED KEY
            if( $key === $search_key && $insert_after_founded_key )
                $new_array[ $insert_key ] = $insert_value;

        }

        // APPEND IF KEY ISNT FOUNDED
        if( $append_if_not_found && count( $array ) == count( $new_array ) )
            $new_array[ $insert_key ] = $insert_value;

        return $new_array;

    }

用法:

    $array1 = array(
        0 => 'zero',
        1 => 'one',
        2 => 'two',
        3 => 'three',
        4 => 'four'
    );

    $array2 = array(
        'zero'  => '# 0',
        'one'   => '# 1',
        'two'   => '# 2',
        'three' => '# 3',
        'four'  => '# 4'
    );

    $array3 = array(
        0 => 'zero',
        1 => 'one',
       64 => '64',
        3 => 'three',
        4 => 'four'
    );


    // INSERT AFTER WITH NUMERIC KEYS
    print_r( insert_into_array( $array1, 3, 'three+', 'three+ value') );

    // INSERT AFTER WITH ASSOC KEYS
    print_r( insert_into_array( $array2, 'three', 'three+', 'three+ value') );

    // INSERT BEFORE
    print_r( insert_into_array( $array3, 64, 'before-64', 'before-64 value', false) );

    // APPEND IF SEARCH KEY ISNT FOUNDED
    print_r( insert_into_array( $array3, 'undefined assoc key', 'new key', 'new value', true, true) );

结果:

Array
(
    [0] => zero
    [1] => one
    [2] => two
    [3] => three
    [three+] => three+ value
    [4] => four
)
Array
(
    [zero] => # 0
    [one] => # 1
    [two] => # 2
    [three] => # 3
    [three+] => three+ value
    [four] => # 4
)
Array
(
    [0] => zero
    [1] => one
    [before-64] => before-64 value
    [64] => 64
    [3] => three
    [4] => four
)
Array
(
    [0] => zero
    [1] => one
    [64] => 64
    [3] => three
    [4] => four
    [new key] => new value
)

这可以通过array.splice()来实现。请注意，array_splice或array_merge不会为关联数组保留键。因此使用array_slice和'+'操作符来连接两个数组。

详情请点击这里

$array_1 = array(
    '0' => 'zero',
    '1' => 'one',
    '2' => 'two',
    '3' => 'three',
  );
  
  $array_2 = array(
    'zero'  => '0',
    'one'   => '1',
    'two'   => '2',
    'three' => '3',
  );
  $index = 2;
  $finalArray = array_slice($array_1, 0, $index, true) +
                $array2  +
                array_slice($array_2, $index, NULL, true);
print_r($finalArray);
/*
Array
(
    [0] => zero
    [1] => one
    [10] => grapes
    [z] => mangoes
    [two] => 2
    [three] => 3
)
*/

以下是我的看法:

/**
 * 
 * Insert an element after an index in an array
 * @param array $array  
 * @param string|int $key 
 * @param mixed $value
 * @param string|int $offset
 * @return mixed
 */
function array_splice_associative($array, $key, $value, $offset) {
    if (!is_array($array)) {
        return $array;
    }
    if (array_key_exists($key, $array)) {
        unset($array[$key]);
    }
    $return = array();
    $inserted = false;
    foreach ($array as $k => $v) {
        $return[$k] = $v;
        if ($k == $offset && !$inserted) {
            $return[$key] = $value;
            $inserted = true;
        }
    }
    if (!$inserted) {
        $return[$key] = $value;
    }


    return $return;
}

使用array_splice而不是array_slice可以减少一次函数调用。

$toto =  array(
  'zero'  => '0',
  'one'   => '1',
  'two'   => '2',
  'three' => '3'
);
$ret = array_splice($toto, 3 );
$toto = $toto +  array("my_key" => "my_value") + $ret;
print_r($toto);

试试这个===

$key_pos=0;
$a1=array("a"=>"red", "b"=>"green", "c"=>"blue", "d"=>"yellow");
$arrkey=array_keys($a1);
array_walk($arrkey,function($val,$key) use(&$key_pos) {
  if($val=='b')
    {
        $key_pos=$key;
    }
  });
$a2=array("e"=>"purple");
$newArray = array_slice($a1, 0, $key_pos, true) + $a2 +
        array_slice($a1, $key_pos, NULL, true);
print_r($newArray);

输出

Array (
      [a] => red
      [e] => purple
      [b] => green
      [c] => blue
      [d] => yellow )

你可以在foreach循环中插入元素，因为这个循环工作在原始数组的副本上，但是你必须跟踪插入的行数(在这段代码中我称之为“膨胀”):

$bloat=0;
foreach ($Lines as $n=>$Line)
    {
    if (MustInsertLineHere($Line))
        {
        array_splice($Lines,$n+$bloat,0,"string to insert");
        ++$bloat;
        }
    }

显然，您可以推广这种“膨胀”思想来处理foreach循环期间的任意插入和删除。