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array_splice

(PHP 4, PHP 5)

array_splice --  把数组中的一部分去掉并用其它值取代

说明

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

array_splice() 把 input 数组中由 offset 和 length 指定的单元去掉，如果提供了 replacement 参数，则用 replacement 数组中的单元取代。返回一个包含有被移除单元的数组。注意 input 中的数字键名不被保留。

如果 offset 为正，则从 input 数组中该值指定的偏移量开始移除。如果 offset 为负，则从 input 末尾倒数该值指定的偏移量开始移除。

如果省略 length，则移除数组中从 offset 到结尾的所有部分。如果指定了 length 并且为正值，则移除这么多单元。如果指定了 length 并且为负值，则移除从 offset 到数组末尾倒数 length 为止中间所有的单元。小窍门：当给出了 replacement 时要移除从 offset 到数组末尾所有单元时，用 count($input) 作为 length。

如果给出了 replacement 数组，则被移除的单元被此数组中的单元替代。如果 offset 和 length 的组合结果是不会移除任何值，则 replacement 数组中的单元将被插入到 offset 指定的位置。注意替换数组中的键名不保留。如果用来替换的值只是一个单元，那么不需要给它加上 array()，除非该单元本身就是一个数组。

以下表达式以同样方式修改了 $input：

表格 1. array_splice() 等价表达式

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] = $y // 对于键名和偏移量等值的数组 array_splice($input, $x, 1, $y)

返回一个包含被移除单元的数组。

例子 1. array_splice() 例子

<?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");
?>

参见 array_slice()，unset() 和 array_merge()。


add a note add a note User Contributed Notes
bdjumakov at gmail dot com
01-Sep-2006 03:11
Someone might find this function usefull. It just takes a given element from the array and moves it before given element into the same array.

<?php
function array_move($which, $where, $array)
{
   $tmp  = array_splice($array, $which, 1);
   array_splice($array, $where, 0, $tmp);
   return $array;
}
?>
Paul
12-Feb-2006 02:06
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
10-Feb-2006 11:35
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
07-Dec-2005 10:35
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 10:03
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 08:53
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 09:54
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 05:31
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 04:52
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 10:48
<?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
18-Jul-2004 12:45
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)
17-Jul-2004 12:18
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 07:15
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
30-May-2004 11:19
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
31-Mar-2004 04:16
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 08:30
//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
06-Feb-2004 06:16
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
04-Nov-2003 03:56
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
27-Aug-2003 05:51
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 06:57
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
12-Aug-2003 03:40
[ 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
02-Jul-2003 07:18
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 10:12
<?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
15-Apr-2003 04:59
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
23-Nov-2002 06:27
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
12-Nov-2002 02:56
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.
19-Jun-2002 10:14
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
13-Jun-2002 12:59
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 05:55
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
07-Jun-2002 02:21
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
07-Jun-2002 02:09
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
07-Jun-2002 11:26
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 10:02
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 09:36
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
15-Feb-2002 03:54
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 06:09
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
16-Jan-2002 11:32
array_splice resets the internal pointer of $input.  In fact, many array functions do this.  Caveat programmor!
brissaille at yahoo dot com
22-Dec-2000 03:31
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
23-Oct-2000 09:16
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);
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