I need <?php array_Splice()?> function, that use array keys instead of order (offset and length) because of associated arrays, and this is result:

<?php
/**
 *    first variation
 *
 *    $input is input array
 *    $start is index of slice begin
 *    $end is index of slice end, if this is null, $replacement will be inserted (in the same way as original array_Slice())
 *indexes of $replacement are preserved in both examples
 */
function array_KSplice1(&$input, $start, $end=null, $replacement=null)
{
    $keys=array_Keys($input);
    $values=array_Values($input);
    if($replacement!==null)
    {
        $replacement=(array)$replacement;
        $rKeys=array_Keys($replacement);
        $rValues=array_Values($replacement);
    }

    $start=array_Search($start,$keys,true);
    if($start===false)
        return false;
    if($end!==null)
    {
        $end=array_Search($end,$keys,true);
        // if $end not found, exit
        if($end===false)
            return false;
        // if $end is before $start, exit
        if($end<$start)
            return false;
        // index to length
        $end-=$start-1;
    }

    // optional arguments
    if($replacement!==null)
    {
        array_Splice($keys,$start,$end,$rKeys);
        array_Splice($values,$start,$end,$rValues);
    }
    else
    {
        array_Splice($keys,$start,$end);
        array_Splice($values,$start,$end);
    }

    $input=array_Combine($keys,$values);

    return $input;
}

/**
 *    second variation
 *
 *    $input is input array
 *    $start is index of slice begin
 *    $length is length of slice, what will be replaced, if is zero, $replacement will be inserted (in the same way as original array_Slice())
 */
function array_KSplice2(&$input, $start, $length=0, $replacement=null)
{
    $keys=array_Keys($input);
    $values=array_Values($input);
    if($replacement!==null)
    {
        $replacement=(array)$replacement;
        $rKeys=array_Keys($replacement);
        $rValues=array_Values($replacement);
    }

    $start=array_Search($start,$keys,true);
    if($start===false)
        return false;

    // optional arguments
    if($replacement!==null)
    {
        array_Splice($keys,$start,$length,$rKeys);
        array_Splice($values,$start,$length,$rValues);
    }
    else
    {
        array_Splice($keys,$start,$length);
        array_Splice($values,$start,$length);
    }

    $input=array_Combine($keys,$values);

    return $input;
}

$array=range(1,10);
var_Dump(array_KSplice1($array,3,3,array(100=>101,102,103,104)));

$array=range(1,10);
var_Dump(array_KSplice2($array,3,3,array(100=>101,102,103,104)));

?>

Both examples output:
array(11) {
  [0]=>
  int(1)
  [1]=>
  int(2)
  [2]=>
  int(3)
  [100]=>
  int(101)
  [101]=>
  int(102)
  [102]=>
  int(103)
  [103]=>
  int(104)
  [6]=>
  int(7)
  [7]=>
  int(8)
  [8]=>
  int(9)
  [9]=>
  int(10)
}