数组 函数
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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()input 数组中由 offsetlength 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 offsetlength 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

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。

Example #1 array_splice() 例子

<?php
$input 
= array("red""green""blue""yellow");
array_splice($input2);
// $input is now array("red", "green")

$input = array("red""green""blue""yellow");
array_splice($input1, -1);
// $input is now array("red", "yellow")

$input = array("red""green""blue""yellow");
array_splice($input1count($input), "orange");
// $input is now array("red", "orange")

$input = array("red""green""blue""yellow");
array_splice($input, -11, array("black""maroon"));
// $input is now array("red", "green",
//          "blue", "black", "maroon")

$input = array("red""green""blue""yellow");
array_splice($input30"purple");
// $input is now array("red", "green",
//          "blue", "purple", "yellow");
?>

参见 array_slice()unset()array_merge()


数组 函数
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PHP手册 - N: 把数组中的一部分去掉并用其它值取代

用户评论:

mrsohailkhan at gmail dot com (21-Oct-2011 08:34)

array_splice, split an array into 2 arrays. The returned arrays is the 2nd argument actually and the used array e.g $input here contains the 1st argument of array, e.g

<?php
$input
= array("red", "green", "blue", "yellow");
print_r(array_splice($input, 3)); // Array ( [0] => yellow ) 
print_r($input); //Array ( [0] => red [1] => green [2] => blue )
?>

if you want to replace any array value do simple like that,

first search the array index you want to replace

<?php $index = array_search('green', $input);// index = 1 ?>

and then use it as according to the definition

<?php
array_splice
($input, $index, 1, array('mygreeen')); //Array ( [0] => red [1] => mygreeen [2] => blue [3] => yellow )
?>

so here green is replaced by mygreen.

here 1 in array_splice above represent the number of items to be replaced. so here start at index '1' and replaced only one item which is 'green'

news_yodpeirs at thoftware dot de (20-Jul-2011 04:20)

Sometimes you may want to insert one array into another and just work on with the resulting array. array_splice() doesn't support this, as the resulting array isn't the returned value but the first argument, which is changed by reference.

Therefore you may use the following function, which inserts array $ins in array $src at position $pos. $rep can be used if $ins shouldn't be just inserted, but should replace some existing elements (the number of elements to be replaced is given in $rep).

<?php
function array_insert($src,$ins,$pos,$rep=0) {
 
array_splice($src,$pos,$rep,$ins);
  return(
$src);
}
?>

doug at badblue dot com (13-Apr-2011 04:10)

Unexpected behavior if you're trying to use array_splice to truncate an array.  For example:

 <?php $aOut = array_splice($aIn, 300); ?>

If sizeof($aIn) < 300, the entire $aOut array gets wiped out!  The extra conditional is needed to ensure this doesn't happen:

<?php
 
if (sizeof($aIn) > MAX_WINDOW_COUNT) {
  
$aOut = array_splice($aIn, MAX_WINDOW_COUNT);
 }
?>

[PHP 5.3.6]

charette dot s at gmail (21-Jul-2010 04:26)

If you want to append null values wrap them in an array:

<?php

    $a
= array('Hey', 'hey', 'my', 'my');
   
array_splice($a, 1, 0, null);
   
print_r($a);

?>
Array
(
    [0] => Hey
    [1] => hey
    [2] => my
    [3] => my
)

<?php

    $b
= array('Hey', 'hey', 'my', 'my');
   
array_splice($b, 1, 0, array(null));
   
print_r($b);

?>
Array
(
    [0] => Hey
    [1] =>
    [2] => hey
    [3] => my
    [4] => my
)

news_yodpeirs at thoftware dot de (01-Apr-2010 09:32)

Splicing with NULL as replacement may result in unexpected behavior too. Typecasting NULL into an array results in an empty array (as "(array)NULL" equals "array()"). That means, instead of creating an element with value NULL just no new element ist created (just as if there was no replacement specified).

If you want the splicing to create a new element with value NULL you have to use "array(NULL)" instead of NULL.

You should expect this if you read the explanation carefully, but just as objects are considered as a special case for replacement, NULL should be too.

The explanation of replacement better should read: "If replacement is just one element it is not necessary to put array() around it, unless the element is an array itself, an object or NULL."

And the note better should be: "If replacement is not an array, it will be typecast to one (i.e. (array) $parameter). This may result in unexpected behavior when using an object or NULL replacement."

jmtc

daniele centamore (02-Aug-2009 03:48)

just useful functions to move an element using array_splice.

<?php

// info at danielecentamore dot com

// $input  (Array) - the array containing the element
// $index (int) - the index of the element you need to move

function moveUp($input,$index) {
     
$new_array = $input;
     
       if((
count($new_array)>$index) && ($index>0)){
                
array_splice($new_array, $index-1, 0, $input[$index]);
                
array_splice($new_array, $index+1, 1);
             }

       return
$new_array;
}

function
moveDown($input,$index) {
      
$new_array = $input;
        
       if(
count($new_array)>$index) {
                
array_splice($new_array, $index+2, 0, $input[$index]);
                
array_splice($new_array, $index, 1);
             }
  
       return
$new_array;
 } 

$input = array("red", "green", "blue", "yellow");

$newinput = moveUp($input, 2);
// $newinput is array("red", "blue", "green", "yellow")

$input = moveDown($newinput, 1);
// $input is array("red", "green", "blue", "yellow")

?>

strata_ranger at hotmail dot com (01-Jul-2009 07:53)

Should you want a similar function for splicing strings together, here is a rough equivalent:

<?php
function str_splice($input, $offset, $length=null, $splice='')
{
 
$input = (string)$input;
 
$splice = (string)$splice;
 
$count = strlen($input);
 
 
// Offset handling (negative values measure from end of string)
 
if ($offset<0) $offset = $count + $offset;

 
// Length handling (positive values measure from $offset; negative, from end of string; omitted = end of string)
 
if (is_null($length)) $length = $count;
  elseif (
$length < 0$length = $count-$offset+$length;

 
// Do the splice
 
return substr($input, 0, $offset) . $splice . substr($input, $offset+$length);
}

$string = "The fox jumped over the lazy dog.";

// Outputs "The quick brown fox jumped over the lazy dog."
echo str_splice($string, 4, 0, "quick brown ");

?>

Obviously this is not for cases where all you need to do is a simple search-and-replace.

dead dot screamer at seznam dot cz (12-Feb-2009 01:28)

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)
}

Ulrich (01-Nov-2008 01:34)

If you have multidimensional array like
<?php
$arr
= array(array("a"=>1,"b"=>2),array("a"=>7,"b"=>-34));
?>
you can insert elements using array(array(...)). For example:
<?php
array_splice
($arr, 1, 0, array(array("a"=>100, "b"=>77)))
?>

madmax at max-worlds dot net (24-Sep-2008 02:23)

Note:  If replacement is not an array, it will be typecast to one (i.e. (array) $parameter). This may result in unexpected behavior when using an object replacement . 

Example :

<?php
class A()
{
    private
$a;
    private
$b;
    public function
__construct()
    {
       
$this->a = "foo";
       
$this->b = "bar";
    }
}

$array = array();
array_splice($array, 0, 0, new A());
print_r($array);
?>

Outputs :

Array : Array
{
    [0] => foo
    [1] => bar
}

Solution : Enforce the array() on the object.

<?php
array_splice
($array, 0, 0, array(new Object());
?>

Source : http://bugs.php.net/bug.php?id=44485

loushou - life dot 42 at gmail dot com (28-Jul-2008 12:39)

i miss posted the actual function...
here is the real one lol

<?php

function q_sort(&$Info, $Index, $Left, $Right)
{
  echo
"memory usage <b>".memory_get_usage()."</b><br/>\n";
 
$L_hold = $Left;
 
$R_hold = $Right;
 
$Pivot = $Left;
 
$PivotValue = $Info[$Left];
  while (
$Left < $Right)
  {
    while ((
$Info[$Right][$Index] >= $PivotValue[$Index]) && ($Left < $Right))
     
$Right--;
    if (
$Left != $Right)
    {
     
$Info[$Left] = $Info[$Right];
     
$Left++;
    }
    while ((
$Info[$Left][$Index] <= $PivotValue[$Index]) && ($Left < $Right))
     
$Left++;
    if (
$Left != $Right)
    {
     
$Info[$Right] = $Info[$Left];
     
$Right--;
    }
  }
 
$Info[$Left] = $PivotValue;
 
$Pivot = $Left;
 
$Left = $L_hold;
 
$Right = $R_hold;
  if (
$Left < $Pivot)
   
q_sort($Info, $Index, $Left, $Pivot-1);
  if (
$Right > $Pivot)
   
q_sort($Info, $Index, $Pivot+1, $Right);
}

?>

Francis (27-Apr-2008 08:27)

Do you need to sort a 2D array on just one of its variables while trying to preserve somewhat the original order?

<?php

function sort_2d_array($array, $position, $order = "ASC"){
  if (!
is_array($array)) return $array;
  if (
count($array) < 2) return $array;
 
$new = array($array[0]);
  for (
$cnt = 1; $cnt <= count($array) - 1; $cnt++){
   
$stop = 0;
   
$splice = 0;
    for (
$newcnt = 0; $newcnt <= count($new) - 1; $newcnt++){
      if (
$stop == 0){
        if (
$order == "ASC")
        if (
$array[$cnt][$position] < $new[$newcnt][$position]){
         
$splice = $newcnt;
         
$stop = 1;
        }
// splice position for ASC
       
if ($order == "DESC")
        if (
$array[$cnt][$position] > $new[$newcnt][$position]){
         
$splice = $newcnt;
         
$stop = 1;
        }
// splice position for DESC
     
} // stop vying for position
   
} // cycle through new array to find position
   
if ($stop == 0){
     
$new[] = $array[$cnt];
    } else {
     
array_splice($new, $splice, 0, array($array[$cnt]));
    }
// splice into new array while keeping somewhat the original order
 
} // cycle through original array
 
return $new;
}
// sort_2d_array

?>

Application Example: In-House Search Engine
Here we are trying to find the word apple in the website by sort of the most recent occurances first, but the number of occurances first. 

We've already sorted the mysql output by the date desc and have counted the no of occurances and have placed those in an array for the final query. 

I've used this function to further sort the occurances but somewhat keep the original mysql sort order.

Key
[0] Record number
     [0] Record ID
     [1] Source Table
     [2] No of Occurances Pinged

  ---------------------------

[0]
     [0] 24530
     [1] Blogs
     [2] 1

[1]
     [0] 24400
     [1] Blogs
     [2] 1

[2]
     [0] 24240
     [1] Blogs
     [2] 4

[3]
     [0] 243422
     [1] Classifieds
     [2] 1

[4]
     [0] 243100
     [1] Classifieds
     [2] 1

After running...

<?php
sort_2d_array
($array, 2, "DESC");
?>

We have...

[0]
     [0] 24240
     [1] Blogs
     [2] 4

[1]
     [0] 24530
     [1] Blogs
     [2] 1

[2]
     [0] 24400
     [1] Blogs
     [2] 1

[3]
     [0] 243422
     [1] Classifieds
     [2] 1

[4]
     [0] 243100
     [1] Classifieds
     [2] 1

Might be useful to someone...

nash0r (29-Feb-2008 09:04)

array_splice($input, -1) / array_slice($input, 1) equivalent to array_shift($input) ?????

Try this:

<?php
$input
= array('key1' => array('deep1' => 'Value'), 'key2' => array('deep2' => 'Value'), 'key3' => array('deep3' => 'Value'));

$foo_splice = array_splice($input, -1);
$foo_shift = array_shift($input);

echo
"<pre>".print_r($foo_splice, true)."</pre>";
echo
"<pre>".print_r($foo_shift, true)."</pre>";
?>

Output:

Array
(
    [key3] => Array
        (
            [deep3] => Value
        )

)

Array
(
    [deep1] => Value
)

pauljamescampbell at gmail dot com (06-Feb-2008 02:46)

Here's my own take on an array slice method that preserves keys from an associative array.

<?php
/**
 * Array slice function that preserves associative keys
 *
 * @function associativeArraySlice
 *
 * @param  Array  $array  Array to slice
 * @param  Integer  $start   
 * @param  Integer  $end
 *
 * @return  Array
 */
function associativeArraySlice($array, $start, $end) {
   
// Method param restrictions
   
if($start < 0) $start = 0;
    if(
$end > count($array)) $end = count($array);

   
// Process vars
   
$new = Array();
   
$i = 0;

   
// Loop
   
foreach($array as $key => $value) {
        if(
$i >= $start && $i < $end) {
           
$new[$key] = $value;
        }
       
$i++;
    }
    return(
$new);
}
?>

saurabhmdh at yahoo dot co dot on (15-Sep-2007 08:29)

for inserting array in 2-d array, according x position, y position

<?php
function add_module_xy($x_loc, $y_loc, $module) {
   
//identify the column of the modules
   
switch ($x_loc) {
      case
1:
       
$x = 'left';
        break;
      case
2:
       
$x = 'middle';
        break;
      case
3:
       
$x = 'right';
        break;
      default:
        throw new
Exception("", "Invalid horizontal position $x_loc");
    }
   
   
$max_y_loc = count($this->module_arrays[$x]) + 1;
    if (
$y_loc > $max_y_loc) {
     
//if y location is greater then max array index then add module to last
     
$y_loc = $max_y_loc;
    }
   
$left = array_slice ($this->module_arrays[$x], 0, $y_loc-1);
   
$right = array_slice ($this->module_arrays[$x], $y_loc-1);
   
$insert[0] = $module;
   
$array = array_merge ($left, $insert, $right);
   
$this->module_arrays[$x] = $array;

    
  }
?>

mip at ycn dot com (08-Mar-2007 01:37)

Ever wounder what array_splice is doing to your references, then try this little script and see the output.

<?php

$a
= "a";
$b = "b";
$c = "c";
$d = "d";
$arr = array();
$arr[] =& $a;
$arr[] =& $b;
$arr[] =& $c;
array_splice($arr,1,0,array($d));
$sec_arr = array();
$sec_arr[] =& $d;
array_splice($arr,1,0,$sec_arr);

$arr[0] = "test"; // should be $a
$arr[3] = "test2"; // should be $b
$arr[1] = "this be d?"; // should be $d
$arr[2] = "or this be d?"; // should be $d
var_dump($arr);
var_dump($a);
var_dump($b);
var_dump($d);
?>

The output will be (PHP 4.3.3):

array(5) {
  [0]=>
  &string(4) "test"
  [1]=>
  &string(10) "this be d?"
  [2]=>
  string(13) "or this be d?"
  [3]=>
  &string(5) "test2"
  [4]=>
  &string(1) "c"
}
string(4) "test"
string(5) "test2"
string(10) "this be d?"

So array_splice is reference safe, but you have to be careful about the generation of the replacement array.

have fun, cheers!

ahigerd at stratitec dot com (24-Jan-2007 02:07)

A comment on array_merge mentioned that array_splice is faster than array_merge for inserting values. This may be the case, but if your goal is instead to reindex a numeric array, array_values() is the function of choice. Performing the following functions in a 100,000-iteration loop gave me the following times: ($b is a 3-element array)

array_splice($b, count($b)) => 0.410652
$b = array_splice($b, 0) => 0.272513
array_splice($b, 3) => 0.26529
$b = array_merge($b) => 0.233582
$b = array_values($b) => 0.151298

bdjumakov at gmail dot com (31-Aug-2006 08:11)

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 06:06)

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 03:35)

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 02:35)

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" }
?>

weikard at gmx dot de (15-Sep-2005 01:53)

You cannot insert with array_splice an array with your own key. array_splice will always insert it with the key "0".

<?php
// [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);
}

<?php
// [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.

csaba at alum dot mit dot edu (13-Aug-2005 10:31)

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.

<?php
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 09:52)

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!

gideon at i6developments dot com (18-Jul-2004 05:45)

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 05:18)

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]);
          }
}
?>

rolandfoxx at yahoo dot com (30-Mar-2004 08:16)

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.

(18-Aug-2003 11:57)

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 08:40)

[ 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);
?>

plintus at smtp dot ru (14-Apr-2003 09:59)

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 :)

tsunaquake DOESNTLIKESPAM @ wp DOT pl (11-Nov-2002 06:56)

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 03:14)

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 05:59)

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 10:55)

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 07:21)

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 07:09)

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 04:26)

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 03:02)

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.

jrhardytwothousandtwo at yahoo dot com (15-Feb-2002 07:54)

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.

<?php
$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
?>

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.

leingang AT math DOT rutgers DOT edu (16-Jan-2002 03:32)

array_splice resets the internal pointer of $input.  In fact, many array functions do this.  Caveat programmor!