array_splice

(PHP 4, PHP 5)

array_splice --  Удалить последовательность элементов массива и заменить её другой последовательностью

Оисание

array array_splice ( array &input, int offset [, int length [, array replacement]] )

array_splice() удаляет length элементов, расположенных на растоянии offset от начала массива input, и заменяет их элементами массива replacement, если он передан в качестве параметра. Возвращает массив выбранных элементов.

Если параметр offset положителен, будут удалены элементы, находящиеся на расстоянии offset от начала array. Если offset отрицателен, будут удалены элементы, находящиеся на расстоянии offset от конца array.

Если параметр length опущен, будут удалены все элементы начиная с позиции offset и до конца массива. Если передан положительный параметр length, будет удалено length элементов. Если передан отрицательный параметр length, будут удалены элементы исходного массива, начиная с позиции offset и заканчивая позицией, отстоящей на length элементов от конца array. Совет: для того, чтобы удалить все элементы массива, начиная с позиции offset в то время как указан параметр replacement, используйте count($input) в качестве параметра length.

Если передан массив replacement в качестве аргумента, тогда удалённые элементы будут заменены элементами этого массива. Если параметры offset и length таковы, что из исходного массива не будет ничего удалено, тогда элементы массива replacement будут вставлены на позицию offset. Обратите внимание, что ключи массива replacement не сохраняются. Совет: если вам нужно вставить один элемент в массив, нет необходимости заключать его в вызов функции array(), если только этот элемент не является массивом.

Последующие выражения произведут одинаковые изменения в массиве $input:

Таблица 1. Эквиваленты array_splice()

array_push($input, $x, $y) array_splice($input, count($input), 0, array($x, $y))
array_pop($input) array_splice($input, -1)
array_shift($input) array_splice($input, 0, 1)
array_unshift($input, $x, $y) array_splice($input, 0, 0, array($x, $y))
$input[$x] = $y // в случае, если key равен offset array_splice($input, $x, 1, $y)

Возвращает массив, содержащий удалённые элементы.

Пример 1. Примеры использования array_splice()

<?php
$input = array("red", "green", "blue", "yellow");
array_splice($input, 2);
// $input is now array("red", "green")

$input = array("red", "green", "blue", "yellow");
array_splice($input, 1, -1);
// $input is now array("red", "yellow")

$input = array("red", "green", "blue", "yellow");
array_splice($input, 1, count($input), "orange");
// $input is now array("red", "orange")

$input = array("red", "green", "blue", "yellow");
array_splice($input, -1, 1, array("black", "maroon"));
// $input is now array("red", "green",
//          "blue", "black", "maroon")

$input = array("red", "green", "blue", "yellow");
array_splice($input, 3, 0, "purple");
// $input is now array("red", "green",
//          "blue", "purple", "yellow");
?>

См. также array_slice(), unset() и array_merge().



array_splice
Paul
11-Feb-2006 10:06
In PHP 4.3.10, at least, it seems that elements that are inserted as part of the replacement array are inserted BY REFERENCE (that is, as though with the =& rather than = assignment operation). So if your replacement array contains elements that references to variables that you can also access via other variable name, then this will be true of the elements in the final array too.

In particular, this means that it is safe to use array_splice() on arrays of objects, as you won't be creating copies of the objects (as it is so easy to do in PHP 4).
gerry-03 at 4warding dot com
09-Feb-2006 07:35
For anybody who is wondering... jrhardytwothousandtwo's trick for inserting an element using array_splice, will also work with multi-dimensional arrays if you do the following:

<?php
  function array_insert(&$input, $offset, $replacement){
   array_splice($input, $offset, 0, 0);
   $input[$offset] = $replacement;
  }
?>

I'm not sure if this (or a derivative of it) will solve other problems that I have seen just about everybody on here trying to solve. But apart from it's hackish nature, it works well for me.
ajd at cloudiness dot com
06-Dec-2005 06:35
weikard's function below is useful but it will still strip keys from array elements where the key is an integer, whether or not it is in a string:

<?php
function array_insert (&$array, $position, $insert_array) {
  $first_array = array_splice ($array, 0, $position);
  $array = array_merge ($first_array, $insert_array, $array);
}
$f = array("three" => "zzz", "3" => "yyy");
$a = array("4.0" => "zzzz", "four" => "yyyy");
array_insert($a,0,$f);
var_dump($a);
// array(4) { ["three"]=> string(3) "zzz" [0]=> string(3) "yyy"  ["4.0"]=> string(4) "zzzz" ["four"]=> string(4) "yyyy" }
?>
Julien PACHET
03-Dec-2005 06:03
If you want to remove an item of the array, shifting the others values, you can use:

function my_array_unset($array,$index) {
  // unset $array[$index], shifting others values
  $res=array();
  $i=0;
  foreach ($array as $item) {
   if ($i!=$index)
     $res[]=$item;
   $i++;
  }
  return $res;
}
weikard at gmx dot de
15-Sep-2005 05:53
You cannot insert with array_splice an array with your own key. array_splice will always insert it with the key "0".

[DATA]

$test_array = array (
  row1 => array (col1 => 'foobar!', col2 => 'foobar!'),
  row2 => array (col1 => 'foobar!', col2 => 'foobar!'),
  row3 => array (col1 => 'foobar!', col2 => 'foobar!')
);

[ACTION]

array_splice ($test_array, 2, 0, array ('rowX' => array ('colX' => 'foobar2')));
echo '<pre>'; print_r ($test_array); echo '</pre>';

[RESULT]

Array (
   [row1] => Array (
           [col1] => foobar!
           [col2] => foobar!
       )

   [row2] => Array (
           [col1] => foobar!
           [col2] => foobar!
       )

   [0] => Array (
           [colX] => foobar2
       )

   [row3] => Array (
           [col1] => foobar!
           [col2] => foobar!
       )
)

But you can use the following function:

function array_insert (&$array, $position, $insert_array) {
  $first_array = array_splice ($array, 0, $position);
  $array = array_merge ($first_array, $insert_array, $array);
}

[ACTION]

array_insert ($test_array, 2, array ('rowX' => array ('colX' => 'foobar2')));
echo '<pre>'; print_r ($test_array); echo '</pre>';

[RESULT]

Array (
   [row1] => Array (
           [col1] => foobar!
           [col2] => foobar!
       )

   [row2] => Array (
           [col1] => foobar!
           [col2] => foobar!
       )

   [rowX] => Array (
           [colX] => foobar2
       )

   [row3] => Array (
           [col1] => foobar!
           [col2] => foobar!
       )
)

[NOTE]

The position "0" will insert the array in the first position (like array_shift). If you try a position higher than the langth of the array, you add it to the array like the function array_push.
cronodragon_at_gmail
13-Sep-2005 06:54
To delete an element of an array just use unset(). Example:

// Deletes the element with the key "quux" from array $bar
unset($bar['quux']);

Easy! =)
csaba at alum dot mit dot edu
13-Aug-2005 02:31
Appending arrays
If you have an array $a2 whose values you would like to append to an array $a1 then four methods you could use are listed below in order of increasing time.  The last two methods took significantly more time than the first two.  The most surprising lesson is that using the & incurs a time hit.

foreach ($a2 as $elem) $a1[]=$elem;
foreach ($a2 as &$elem) $a1[]=$elem;
array_splice ($a1, count($a1), 0, $a2);
$a1 = array_merge($a1, $a2);

Csaba Gabor from Vienna
randomdestination at gmail dot com
22-Jul-2005 01:52
To split an associative array based on it's keys, use this function:

<?php
function &array_split(&$in) {
   $keys = func_get_args();
   array_shift($keys);
  
   $out = array();
   foreach($keys as $key) {
       if(isset($in[$key]))
           $out[$key] = $in[$key];
       else
           $out[$key] = null;
       unset($in[$key]);
   }
  
   return $out;
}
?>

Example:
<?php
$testin = array('a' => 1, 'b' => 2, 'c' => 3, 'd' => 4);
$testout =& array_split($testin, 'a', 'b', 'c');

print_r($testin);
print_r($testout);
?>

Will print:

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

Hope this helps anyone!
fontajos at phpeppershop dot com
15-Apr-2005 07:48
<?php
  // This function deletes a element in an array, by giving it the name of a key.
  function delArrayElementByKey($array_with_elements, $key_name) {
     $key_index = array_keys(array_keys($array_with_elements), $key_name);
     if (count($key_index) != '') {
         // Es gibt dieses Element (mindestens einmal) in diesem Array, wir loeschen es:
         array_splice($array_with_elements, $key_index[0], 1);
     }
     return $array_with_elements;
  }// End function delArrayElementByKey
?>
gideon at i6developments dot com
17-Jul-2004 09:45
array_splice dynamically updates the total number of entries into the array. So for instance I had a case where I needed to insert a value into every 4th entry of the array from the back. The problem was when it added the first, because the total number was dynamically updated, it would only add after the 3rd then the 2nd and so one. The solution I found is to track the number of inserts which were done and account for them dynamically.

Code:
<?php
   $modarray = array_reverse($mili);
   $trig=1;
       foreach($modarray as $rubber => $glue) {
           if($rubber!="<BR>") {
           $i++;
           $b++;
           if ($i==4) {
               $trig++;
               if($trig<=2) {
               array_splice($modarray,$b,0,"<BR>");
               }elseif($trig>=3){
               array_splice($modarray,$b+($trig-2),0,"<BR>");
               }
               $i=0;
               };
               };
       };   
   $fixarray = array_reverse($modarray);

?>
jtgt at gmx dot de (Richard Lachmann)
16-Jul-2004 09:18
This function will preserve keys:

<?php
function my_array_splice(&$_arr, $_index, $_long){
           $_keys=array_keys($_arr);
           $_key=array_search($_index, $_keys);
           if ( $_key !== FALSE ){
               $_keys=array_splice($_keys, $_key, $_long);
             foreach ($_keys as $_key) unset($_arr[$_key]);
         }
}
?>
reverse esacdaehasinhoj at oohay dot moc
28-Jun-2004 04:15
Also, a quick function to discard empty entries in an array which otherwise keeps keys intact:

<?php

  function remove_empty($inarray) {

     if (is_array($inarray)) {

         foreach($inarray as $k=>$v) {
             if (!(empty($v))) {
                 $out[$k]=$v;
             }
         }

         return $out;

     } else {
         return $inarray;
     }

  }

  // easy enough?

  print_r(remove_empty(array('', 'foo', '', 'bar', '', '', 'baz', '')));

?>

Should return:

Array
(
   [1] => foo
   [3] => bar
   [6] => baz
)
cyril carrez
29-May-2004 08:19
array_splice does work when replacing with objects. As stated in the manual, you have to embed the object in an array:

<?php
array_splice ($myarray, $offset, 0, Array($myobjet));
?>
rolandfoxx at yahoo dot com
30-Mar-2004 12:16
Be careful, array_splice does not behave like you might expect should you try to pass it an object as the replacement argument.  Consider the following:

<?php
//Very truncated
class Tree {
  var $childNodes

  function addChild($offset, $node) {
   array_splice($this->childNodes, $offset, 0, $node);
   //...rest of function
  }

}

class Node {
  var $stuff
  ...
}

$tree = new Tree();
// ...set 2 nodes using other functions...
echo (count($tree->childNodes)); //Gives 2
$newNode = new Node();
// ...set node attributes here...
$tree->addChild(1, $newNode);
echo(count($tree->childNodes)); //Expect 3?  wrong!
?>

In this case, the array has a number of items added to it equal to the number of attributes in the new Node object and the values thereof  I.e, if your Node object has 2 attributes with values "foo" and "bar", count($tree->childNodes) will now return 4, with the items "foo" and "bar" added to it.  I'm not sure if this qualifies as a bug, or is just a byproduct of how PHP handles objects.

Here's a workaround for this problem:
function array_insertobj(&$array, $offset, $insert) {
  $firstPart = array_slice($array, 0, $offset);
  $secondPart = array_slice($array, $offset);
  $insertPart = array($insert);
  $array = array_merge($firstPart, $insertPart, $secondPart);
}

Note that this function makes no allowances for when $offset equals the first or last index in the array.  That's because array_unshift and array_push work just fine in those cases.  It's only array_splice that can trip you up.  Obviously, this is kinda tailor-made for arrays with numeric keys when you don't really care what said keys are, but i'm sure you could adapt it for associative arrays if you needed it.
bitmor.co.kr
19-Feb-2004 04:30
//orginal
IndexKey Bad Police
richard at richard-sumilang dot com
23-Nov-2002 04:27

<?php
   function array_slice2($array, $val, $slice="name"){
       switch($slice){
           case "name":
               while(list($i,$k)=each($array)){
                   if( $i != $val) { $return[$i]=$array[$i];  print "i = $i,val = $val<br>";}
                   else print " exit BugShow i = $i,val = $val <br>";
               }
               break;
           case "variable":
               while(list($i)=each($array)){
                   if($array[$i]!=$val) $return[$i]=$array[$i];
               }
               break;
       }
       return $return;
   }

   $list = array( "0" => "zero", "1" => "one", "2" => "two", "3" => "three", "4" => "four", "5" => "five", "6" => "six");
   print_r( array_slice2 ( $list,'tne') );echo "<br>";

   //YouWantShow    ? Array ( [0] => zero [1] => one [2] => two [3] => three [4] => four [5] => five [6] => six )
   //But BugShow    ? Array ( [1] => one [2] => two [3] => three [4] => four [5] => five [6] => six )

   //PrintShow
   //exit BugShow i = 0,val = tne
   //i = 1,val = tne
   //i = 2,val = tne
   //i = 3,val = tne
   //i = 4,val = tne
   //i = 5,val = tne
   //i = 6,val = tne
?>

 

<?php
   print_r( array_slice2 ( $list,"one","variable") );echo "<br>";
   //Array ( [0] => zero [2] => two [3] => three [4] => four [5] => five [6] => six )
?>

//
michael at cannonbose dot com
05-Feb-2004 02:16
While trying to find a way to insert some array into another at some index, array_splice seemed like the function that I wanted. The results weren't quite as expected though. Of course, I can be using it wrong.

My desired results turned out be $array1 after calling array_splice() and no tuning got me to have $array3 with what was showing up in $array1.

[code]
<?php
       $array1                = array(1, 2, 3, 7, 8, 9);
       $array2                = array(4, 5, 6);
       echo '<br />array1 :: ';
       print_r( $array1 );
       echo '<br />array2 :: ';
       print_r( $array2 );

       $index                  = 3;
       // $length                  = count($array1);
       // $length                  = -1;
       $length                = 0;

       // array1 is call by reference it seems
       $array3                = array_splice($array1, $index, $length,
                                   $array2);

       echo '<br />array1 :: ';
       print_r( $array1 );
       echo '<br />array2 :: ';
       print_r( $array2 );
       echo '<br />array3 :: ';
       print_r( $array3 );
?>
[/code]

Results in
[code]
array1 :: Array ( [0] => 1 [1] => 2 [2] => 3 [3] => 7 [4] => 8 [5] => 9 )
array2 :: Array ( [0] => 4 [1] => 5 [2] => 6 )
array1 :: Array ( [0] => 1 [1] => 2 [2] => 3 [3] => 4 [4] => 5 [5] => 6 [6] => 7 [7] => 8 [8] => 9 )
array2 :: Array ( [0] => 4 [1] => 5 [2] => 6 )
array3 :: Array ( )
[/code]

Cheers,

Michael
roeltje.com
03-Nov-2003 11:56
In reply on the message "18-Aug-2003 09:57"

If you want to insert a value into some array

<?
// I think we can replace
array_splice($array, 3, count($array), array_merge(array('x'), array_slice($array, 3)));

// with for inserting multiple values
array_splice($array, 3, 0, array('x','y'));

// or for just inserting 1 value
array_splice($array, 3, 0, 'x');
?>

Sounds to me a lot faster.

  Roeltje...
Juan Guillermo Fernndez
26-Aug-2003 02:51
Just fenced the infamous problem of the Associative Arrays v/s array_splice.

I've done this little function to get around it. It seems to work pretty well, by I'm kind of a novice in this so I'm sure you'll find bugs, or better ways to do it:

<?php
function ass_array_splice
( $in_arr,
  $desp,
  $size,
  $sust,
  $new_key='')
{
 $head=array_slice($in_arr,0,$desp);
 $tale=array_slice($in_arr,$desp+$size);
 if ($new_key!='')
   $arr_res=array_merge($head,
                                 array($new_key=>$sust),
                                 $tale);
 else $arr_res=array_merge( $head,
                                     $sust,
                                     $tale);
 return $arr_res;
}
?>

that's it. You call it like this:

<?php
$P=ass_array_splice($_P,
                             18,
                               3,
 $P['FechD'].'/'.$P['FechM'].'/'.$P['FechA'],'Fech');
?>

this example merges three cells from the array, and replace themselves with the result, calling the new cell 'Fech'. If you omit the last param, it calls the cel '0', just like old array_splice does.

thanks for any feedback!
18-Aug-2003 03:57
Want to insert a new value in the middle of the array, without overwriting other elements? Try this.

<?php
$array = array(
   0 => 0,
   1 => 1,
   2 => 2,
   3 => 3,
   4 => 4,
   5 => 5
);
array_splice($array, 3, count($array), array_merge(array('x'), array_slice($array, 3)));
echo '<pre>';
print_r($array);
?>

Output:
Array
(
   [0] => 0
   [1] => 1
   [2] => 2
   [3] => x
   [4] => 3
   [5] => 4
   [6] => 5
)

As you can see, the operation add 'X' in the 4th place, pushing everything else to the next key.
kbrown at horizon dot sk dot ca
11-Aug-2003 12:40
[ Editor's Note: If you're not concerned with the indexes being contiguously numbered (such as for an associative array) then unset($ar[$ind]); will accomplish the same as the code below without requiring splice/splice/merge.  If contiguous numbering IS a concern (such as for indexed arrays), you can still save time by using: unset($ar[$ind]); $ar = array_values($ar); ]

Removing elements from arrays

This works better - much quicker

<?php
$ar = array("einstein", "bert", "colin", "descartes", "renoir");
$a = array_slice($ar, 0, $ind);
$b = array_slice($ar, $ind + 1);
$ar = array_merge($a, $b);
?>
cwahl at prisma dot com
01-Jul-2003 04:18
I couldn't get array_splice() to insert into a multidimensional array, so I cribbed this from the notes for array_push() (a thousand thanks to jhall at jadeinternet dot net).  I'm dealing with a spreadsheet-looking dataset, and it lets me add "rows" where the row data is the array that I have assigned to $val, and the row number is $ky:

<?php
function insert_into_array($array,$ky,$val)
{
$n = $ky;
foreach($array as $key => $value)
  {
   $backup_array[$key] = $array[$key];
  }
$upper_limit = count($array);
while($n <= $upper_limit)
  {
   if($n == $ky)
     {
$array[$n] = $val;
echo $n;
     }
   else
     {
$i = $n - "1";
$array[$n] = $backup_array[$i];
     }
   $n++;
  }
return $array;
}
?>

So that:

<?php
$list = array( "0" => "zero",
     "1" => "one",
     "2" => "two",
     "3" => "three",
   "4" => "four",
     "5" => "five",
     "6" => "six");
$value = "New Number Three";
$key = "3";
$new = insert_into_array($list,$key, $value);
?>

Will Return:

$list =
Array
(
   [0] => zero
   [1] => one
   [2] => two
   [3] => three
   [4] => four
   [5] => five
   [6] => six
)

$new=
Array
(
   [0] => zero
   [1] => one
   [2] => two
   [3] => New Number Three
   [4] => three
   [5] => four
   [6] => five
   [7] => six
)
kerxen at caramail dot com
27-May-2003 07:12
<?php
/** **************************
* Document::tableColumn()
*
* { This function sends back a column of the table or the table itself if it has only one column.
*  Input : $table, a table at 1 ou 2 dimensions or more
*          $numeroCol, the number of the column.
*  Output : $output : the column $numero of the table or the table.
*  }
*
**********  **********/

function tableColumn ( $table,  $numeroCol)
{
$output = array();
reset ($table) ;
if (!is_integer($numeroCol)) $numeroCol=0;
if (count($table)==0) return "UNDEFINED";
else { foreach ($table as $ligne)    // $ligne est un tableau (si $table est en 2D) ou un string ($table en 1D)
       { if (gettype($ligne)!="array")
           {
           if (strlen($ligne)!=0) array_push ($output, $ligne) ;    // on met le string dans $output
           else array_push ($output, " ") ;                        // on met une chaine " " dans $output
           }
         else
           {
           if (strlen($ligne[$numeroCol])!=0) array_push ($output, $ligne[$numeroCol]) ;    // on insere la colonne $numero de la ligne dans $output
           else  array_push ($output, " ") ;                                          // on met une chaine " " dans $output
           }
       }
       return $output;
     }
}
?>

/***************************/
SYNOPTIC : how to use it :
/***************************/

try the exemple below :

<?php
$stack = array ("orange", "banane");
array_push ($stack, "pomme", "bleuet");
$stock =  array ($stack,$stack);

print_r ($stock); echo '<br>';
print_r ($stack); echo '<br>';
print_r (tableColumn ($stock,0)) ;  echo '<br>';
print_r (tableColumn ($stock,1)) ;  echo '<br>';
print_r (tableColumn ($stock,2)) ;  echo '<br>';
print_r (tableColumn ($stock,3)) ;  echo '<br>';
print_r (tableColumn ($stack,0)) ;  echo '<br>';
print_r (tableColumn ($stack,1)) ;  echo '<br>';
?>

YOU WILL GET THIS :

Array ( [0] => Array ( [0] => orange [1] => banane [2] => pomme [3] => bleuet ) [1] => Array ( [0] => orange [1] => banane [2] => pomme [3] => bleuet ) )
Array ( [0] => orange [1] => banane [2] => pomme [3] => bleuet )
Array ( [0] => orange [1] => orange )
Array ( [0] => banane [1] => banane )
Array ( [0] => pomme [1] => pomme )
Array ( [0] => bleuet [1] => bleuet )
Array ( [0] => orange [1] => banane [2] => pomme [3] => bleuet )
Array ( [0] => orange [1] => banane [2] => pomme [3] => bleuet )

/**************************/

Good Luck
Eddy Cingala
plintus at smtp dot ru
14-Apr-2003 01:59
key-safe:

<?php
function array_kslice ($array, $offset, $length = 0) {
$k = array_slice (array_keys ($array), $offset, $length);
$v = array_slice (array_values ($array), $offset, $length);
for ($i = 0; $i < count ($k); $i ++) $r[$k[$i]] = $v[$i];
return $r;
}
?>

smth like this. hope you like it more than versions above :)
richard at richard-sumilang dot com
22-Nov-2002 02:27
My function can remove it by its name or if its equal to something. Became useful because I was inserting all the stuff from the post array into the database but the damn submit button kept comming up with the $_POST also so I wrote this function to get rid of it.

-------------------------------------

<?
   /*
       func.array_slice2.php
      
       Removes a slice from an array given the name of
       it or the value
      
       Ex:
       $array=array_slice2($_POST, "submit_button");
   */
   function array_slice2($array, $val, $slice="name"){
       switch($slice){
           case "name":
               while(list($i)=each($array)){
                   if($i!=$val){
                       $return[$i]=$array[$i];
                   }
               }
           break;
          
           case "variable":
               while(list($i)=each($array)){
                   if($array[$i]!=$val){
                       $return[$i]=$array[$i];
                   }
               }
           break;
       }
      
       return $return;
   }
?>
tsunaquake DOESNTLIKESPAM @ wp DOT pl
11-Nov-2002 10:56
It is possible to use a string instead of offset, eg if you want to deletre the entry $myArray['entry'] then you can simply do it like this:

<?php
array_splice($myArray, 'entry', 1);
?>

Note that you can use unset($myArray['entry']) as well but then, it doesn't enable you to remove more than one entry and it doesn't replace anything in the array, if that's what you intend to do.
18-Jun-2002 07:14
Please note that array_splice() 's second argument is an OFFSET and not an INDEX.

Lets say you want to
$array_of_items = array ('nothing','myitem','hisitem','heritem');
$sid = array_search('myitem',$array_of_items);
echo $sid; /* prints out 1, since index element 1 is "myitem" */

Now, lets say we want to remove that "myitem" from the array:

<?php
$array_of_items = array_splice($array_of_items,(1+$sid),1);
?>

Notice how you have to add a one to the $sid variable?  That is because offset item 1 is "nothing" and since $sid is currently 1 (the index of "myitem"), we add 1 more to it to find out
 its OFFSET.

DO NOT DO THIS:
 $array_of_items = array_splice($array_of_items,$sid,1);
paule at cs dot tamu dot edu
12-Jun-2002 09:59
to kokos@lac.lviv.ua:

Good point about the code not doing what you expected.

The failure to check for the insert case like you pointed out is not a bug, however. I didn't add code to handle that because the key of such an added index is more or less undefined in an unordered associative array. Put another way, if your array is associative and not auto-indexed, you most likely care enough about your keys to want to set them explicitly.
kokos at lac dot lviv dot ua
08-Jun-2002 02:55
To paule@cs.tamu.edu :
Sorry, but the fix will still not work properly - when $length=0 (e.g. trying to insert one value) the
   $new_array[$key]=$replacement;
would be immediately followed by
   $new_array[$key]=$value;
and the $replacement will be lost.

What i was trying to point out in my original post is that $input[$x]=$y is NOT equivalent to array_splice($input, $x, 1, $y) . The equivalence mentioned would be true ONLY when $input is <... ghmm... > "automatically enumerated", having its' keys exactly matching offsets of corresponding elements in the array. But, in general case, keys do not match offsets - perhaps this should be explicitly stated in the Description above.
paule at cs dot tamu dot edu
06-Jun-2002 11:21
Aiya, I feel silly. The fix for my code above assumes that your values in the associative array are strings. Ignore the fix code in my last post and use this instead:

<?php
               if(is_array($replacement))
                   foreach($replacement as $r_key=>$r_value)
                       $new_array[$r_key]=$r_value;
               elseif($replacement!==NULL)
                   $new_array[$key]=$replacement;
?>

Sorry again. I feel sheepish.  n.n
paule at cs dot tamu dot edu
06-Jun-2002 11:09
After reading KoKos' post above, I thought that the code I posted right before his should do what he wanted. However, my original post neglected to note the little "Tip" in the documentation above, about a single element replacement.

If one changes the lines in my code above that says:

<?php
               if(is_array($replacement))
                   foreach($replacement as $r_key=>$r_value)
                       $new_array[$r_key]=$r_value;
?>

to instead say:

<?php
               if(is_string($replacement))
                   $new_array[$key]=$replacement;
               elseif(is_array($replacement))
                   foreach($replacement as $r_key=>$r_value)
                       $new_array[$r_key]=$r_value;
?>

that will solve the problem.

Sorry for the omission.
kokos at lac dot lviv dot ua
06-Jun-2002 08:26
It may seem obvious from the above posts, but cost me a bit of
braindamage to figure this out...

Contrary to the equivalence noted on this page
$input[$x] = $y  <==>  array_splice ($input, $x, 1, $y)
array_splice() will not always work as expected,
even provided that you have only INTEGER keys!

The following code:
   $t=array('a','b','c','d','e');
   var_dump($t);

<?php
   unset($t[0],$t[1],$t[3]);
   $t[0]='f';
   var_dump($t);

   array_splice($t,0,1,'g');
   var_dump($t);
?>

Will produce:
array(5) {
  [0]=>
  string(1) "a"
  [1]=>
  string(1) "b"
  [2]=>
  string(1) "c"
  [3]=>
  string(1) "d"
  [4]=>
  string(1) "e"
}
array(3) {
  [2]=>
  string(1) "c"
  [4]=>
  string(1) "e"
  [0]=>
  string(1) "f"
}
array(3) {
  [0]=>
  string(1) "g"
  [1]=>
  string(1) "e"
  [2]=>
  string(1) "f"
}

Note the position of $t[0] in the second call to var_dump().
And of course, array_splice() left it intact, changing $t[2] instead.
This is because it operates the _offset_, not the _index_.  :)
I think that "equivalence note" should be considered buggy.  ;)))

Best wishes.
KoKos.
paule at cs dot tamu dot edu
26-May-2002 07:02
I believe the following is a version of array_slice that solves most of the issues for people that want an associative key offset, rather than an integer.

<?php
function key_array_splice(&$input, $key_ofs, $length=NULL, $replacement=NULL)
{
   // Adjust the length if it was negative or not passed
   if($length===NULL || $length<0)
       $count = $length+count($input);

   // Cycle through the array
   foreach($input as $key=>$value){
       if(!$key_found){
           if($key===$key_ofs){
               $key_found=true;
               if($length!==NULL && $length>=0)
                   $count=$length;
               if(is_array($replacement))
                   foreach($replacement as $r_key=>$r_value)
                       $new_array[$r_key]=$r_value;
           }else
               $new_array[$key]=$value;
       }
       if($key_found){
           if($count>0)
               $ret_array[$key]=$value;
           else
               $new_array[$key]=$value;
       }
       $count--;
   }

   // Finish up
   $input=$new_array;
   return $ret_array;
}
?>

Note that this code needs PHP 4 for the use of the "===" and "!==" operators.
amtiee at hotmail dot com
29-Apr-2002 06:36
The function my_array_splice(), accepts a user defined key of an array.

$aArray ={'Name'=>'ABC','Age'=>'22', 'Sex'=>'M'};
my_array_splice($aArray, 'Age', 1);

So now $aArray will contain only:

['Name'=>'ABC', 'Sex'=>'M']

my_array_splice() internally makes use of array_search(), which is not supported with PHP <= 4.0.4. A solution to this is to sneak into user contributed notes of function array_search(). An alternative submitted by chen.avinadav@vbulletin.com is the solution for this problem.
jrhardytwothousandtwo at yahoo dot com
14-Feb-2002 11:54
A reference is made to INSERT'ing into an array here with array_splice, however its not explained very well.  I hope this example will help others find what took me days to research.

--code begin--
$original_array = array(1,2,3,4,5);
$insert_into_key_position = 3;
$item_to_insert = "blue";

$returned = array_splice($original_array, $insert_into_key_position, 0, $item_to_insert);

$original_array will now show:

1,2,3,blue,4,5
--code end---

Remember that you are telling the array to insert the element into the KEY position.  Thus the elements start with key 0 and so on 0=>1, 1=>2, 2=>3, 3=>blue, 4=>4, 5=>5.  And walla, you've inserted.  I can't say if this is of any value for named keys, or multidimensional arrays.  However it does work for single dimensional arrays.

$returned should be an empty array as nothing was returned.  This would have substance if you were doing a replace instead.
steve at hynding dot com
17-Jan-2002 02:09
Values removed from the array are returned as an array as such:

<?php
$letters = array("a","b","c");
$removed_val = array_splice($letters, 1, 1);
print_r($removed_val);
?>

Printed Result:

Array ( [0] => b )
leingang AT math DOT rutgers DOT edu
15-Jan-2002 07:32
array_splice resets the internal pointer of $input.  In fact, many array functions do this.  Caveat programmor!
brissaille at yahoo dot com
21-Dec-2000 11:31
Pay attention, if the keys of your
array are integer, array_splice will
modify them.

For example:
$t=array('5'=>'Albator', '7'=>'Goldorak', 21=>'Candy');
array_splice($t,0,0) gives you the follwing result:
$t=array {[0]=>'Albator', [1]=>'Goldorak', [2]=>'Candy'}
info at borderblue dot com
22-Oct-2000 06:16
note that unset() works well for associative arrays, but if you have

$blah = array("a","b","c","d");

and you unset($blah[2]), then the other
elements will not shift, i.e., you'll still have $blah[0], $blah[1], and $blah[3].  If you need things to shift, use

array_splice($blah,2,1);

<array_slicearray_sum>
 Last updated: Tue, 15 Nov 2005