PHP 7.0.6 Released

array_slice

(PHP 4, PHP 5, PHP 7)

array_sliceExtract a slice of the array

Description

array array_slice ( array $array , int $offset [, int $length = NULL [, bool $preserve_keys = false ]] )

array_slice() returns the sequence of elements from the array array as specified by the offset and length parameters.

Parameters

array

The input array.

offset

If offset is non-negative, the sequence will start at that offset in the array. If offset is negative, the sequence will start that far from the end of the array.

length

If length is given and is positive, then the sequence will have up to that many elements in it. If the array is shorter than the length, then only the available array elements will be present. If length is given and is negative then the sequence will stop that many elements from the end of the array. If it is omitted, then the sequence will have everything from offset up until the end of the array.

preserve_keys

Note that array_slice() will reorder and reset the numeric array indices by default. You can change this behaviour by setting preserve_keys to TRUE.

Return Values

Returns the slice.

Changelog

Version Description
5.2.4 The default value of the length parameter was changed to NULL. A NULL length now tells the function to use the length of array. Prior to this version, a NULL length was taken to mean a zero length (nothing will be returned).
5.0.2 The optional preserve_keys parameter was added.

Examples

Example #1 array_slice() examples

<?php
$input 
= array("a""b""c""d""e");

$output array_slice($input2);      // returns "c", "d", and "e"
$output array_slice($input, -21);  // returns "d"
$output array_slice($input03);   // returns "a", "b", and "c"

// note the differences in the array keys
print_r(array_slice($input2, -1));
print_r(array_slice($input2, -1true));
?>

The above example will output:

Array
(
    [0] => c
    [1] => d
)
Array
(
    [2] => c
    [3] => d
)

See Also

User Contributed Notes

taylorbarstow at the google mail service
10 years ago
Array slice function that works with associative arrays (keys):

function array_slice_assoc($array,$keys) {
    return array_intersect_key($array,array_flip($keys));
}
worldclimb at 99gmail99 dot com
8 years ago
array_slice can be used to remove elements from an array but it's pretty simple to use a custom function.

One day array_remove() might become part of PHP and will likely be a reserved function name, hence the unobvious choice for this function's names.

<?
function arem($array,$value){
    $holding=array();
    foreach($array as $k => $v){
        if($value!=$v){
            $holding[$k]=$v;
        }
    }   
    return $holding;
}

function akrem($array,$key){
    $holding=array();
    foreach($array as $k => $v){
        if($key!=$k){
            $holding[$k]=$v;
        }
    }   
    return $holding;
}

$lunch = array('sandwich' => 'cheese', 'cookie'=>'oatmeal','drink' => 'tea','fruit' => 'apple');
echo '<pre>';
print_r($lunch);
$lunch=arem($lunch,'apple');
print_r($lunch);
$lunch=akrem($lunch,'sandwich');
print_r($lunch);
echo '</pre>';
?>

(remove 9's in email)
webmaster_nospam at wavesport dot com
13 years ago
This function may surprise you if you use arbitrary numeric values for keys, i.e.

<?php
//create an array
$ar = array('a'=>'apple', 'b'=>'banana', '42'=>'pear', 'd'=>'orange');

print_r($ar);
// print_r describes the array as:
// Array
// (
//    [a] => apple
//    [b] => banana
//    [42] => pear
//    [d] => orange
// )

//use array_slice() to extract the first three elements
$new_ar = array_slice($ar, 0, 3);

print_r($new_ar);
// print_r describes the new array as:
// Array
// (
//    [a] => apple
//    [b] => banana
//    [0] => pear
// )
?>

The value 'pear' has had its key reassigned from '42' to '0'.

When $ar is initially created the string '42' is automatically type-converted by array() into an integer.  array_slice() and array_splice() reassociate string keys from the passed array to their values in the returned array but numeric keys are reindexed starting with 0.
robert dot johnson at icap dot com
1 year ago
array_slice() seems to work on associative arrays and preserves the keys.  I just ran this test on PHP 5.5:

<?php
$test
= array(
   
'a'=>'hello 1',
   
'r'=>'hello 2',
   
'h'=>'hello 3',
   
'w'=>'hello 4',
   
't'=>'hello 5',
   
'n'=>'hello 6',
   
'k'=>'hello 7',
   
'b'=>'hello 8');
print_r( array_slice($test,2,5) );
?>

Output:
Array
(
    [h] => hello 3
    [w] => hello 4
    [t] => hello 5
    [n] => hello 6
    [k] => hello 7
)
Ray.Paseur often uses Gmail
2 years ago
<?php
// CHOP $num ELEMENTS OFF THE FRONT OF AN ARRAY
// RETURN THE CHOP, SHORTENING THE SUBJECT ARRAY
function array_chop(&$arr, $num)
{
   
$ret = array_slice($arr, 0, $num);
   
$arr = array_slice($arr, $num);
    return
$ret;
}
developer at i-space dot org
14 years ago
remember that array_slice returns an array with the current element. you must use array_slice($array, $index+1) if you want to get the next elements.
Nathan - thefiscster510 at gmail dot com
5 years ago
If you want to remove a specified entry from an array i made this mwethod...

<?php
$array
= array("Entry1","entry2","entry3");

$int = 3; //Number of entries in the array
$int2 = 0; //Starter array spot... it will begine its search at 0.
$del_num = 1; //Represents the second entry in the array... which is the one we will happen to remove this time... i.e. 0 = first entry, 1 = second entry, 2 = third...........

$newarray = array(); //Empty array that will be the new array minus the specified entry...
print_r($array) . "<br>";    //print original array contents
print_r($newarray). "<br>"; //print the new empty array

do
{
$user = $array[$int2];
$key = array_search($user, $array);
if (
$key == $del_num)
{

}
else
{
$newarray[] = $array[$int2];
}

$int2 = $int2 + 1;
} while (
$int2 < $int);

print_r($newarray). "<br>"; //print the new array

?>
s0i0m at dreamevilconcepts dot com
7 years ago
Using the varname function referenced from the array_search page, submitted by dcez at land dot ru. I created a multi-dimensional array splice function. It's usage is like so:

$array['admin'] = array('blah1', 'blah2');
$array['voice'] = array('blah3', 'blah4');
array_cut('blah4', $array);

...Would strip blah4 from the array, no matter where the position of it was in the array ^^ Returning this...

Array ( [admin] => Array ( [0] => blah1 [1] => blah2 ) [voice] => Array ( [0] => blah3 ) )

Here is the code...

<?php

 
function varname ($var)
  {
   
// varname function by dcez at land dot ru
   
return (isset($var)) ? array_search($var, $GLOBALS) : false;
  }

  function
array_cut($needle, $haystack)
  {
    foreach (
$haystack as $k => $v)
    {
      for (
$i=0; $i<count($v); $i++)
        if (
$v[$i] === $needle)
        {
          return
array_splice($GLOBALS[varname($haystack)][$k], $i, 1);
          break; break;
        }
    }

?>

Check out dreamevilconcept's forum for more innovative creations!
xananax at yelostudio dot com
5 years ago
<?php
/**
* Reorders an array by keys according to a list of values.
* @param array $array the array to reorder. Passed by reference
* @param array $list the list to reorder by
* @param boolean $keepRest if set to FALSE, anything not in the $list array will be removed.
* @param boolean $prepend if set to TRUE, will prepend the remaining values instead of appending them
* @author xananax AT yelostudio DOT com
*/
function array_reorder(array &$array,array $list,$keepRest=TRUE,$prepend=FALSE,$preserveKeys=TRUE){
   
$temp = array();
    foreach(
$list as $i){
        if(isset(
$array[$i])){
           
$tempValue = array_slice(
               
$array,
               
array_search($i,array_keys($array)),
               
1,
               
$preserveKeys
           
);
           
$temp[$i] = array_shift($tempValue);
            unset(
$array[$i]);
        }
    }
   
$array = $keepRest ?
        (
$prepend?
           
$array+$temp
           
:$temp+$array
       
)
        :
$temp;
}

/** exemple ** /
$a = array(
    'a'    =>    'a',
    'b'    =>    'b',
    'c'    =>    'c',
    'd'    =>    'd',
    'e'    =>    'e'
);
$order = array('c','b','a');

array_reorder($a,$order,TRUE);
echo '<pre>';
print_r($a);
echo '</pre>';
/** exemple end **/
?>
kezzyhko at gmail dot com
9 months ago
( If $offset is negative and abs($length)>count($length) ) or ( $offset>count($array) ) etc, array_slice returns empty array. For example:

<?php

$array
= array(
   
'a'=>'1',
   
'b'=>'2',
   
'c'=>'3',
   
'd'=>'4',
   
'e'=>'5',
   
'f'=>'6',
   
'g'=>'7',
   
'h'=>'8'
);

print_r( array_slice($test, 2, -10) );
print_r( array_slice($test, 10, 1) );
print_r( array_slice($test, 10, 15) );

//prints
//Array()
//Array()
//Array()

?>
Anonymous
9 years ago
If you specify the fourth argument (to not reassign the keys), then there appears to be no way to get the function to return all values to the end of the array. Assigning -0 or NULL or just putting two commas in a row won't return any results.
richardpq at gmail dot com
9 months ago
@robert_johnson is incorrect, is not that php 5.5 preserver the keys is that the documentation is very clear:

"...will reorder and reset the numeric array indices" so the key here is NUMERIC array indices, therefor:
<?php
$test
= array(
   
1=>'hello 1',
   
2=>'hello 2',
   
3=>'hello 3',
   
4=>'hello 4',
   
5=>'hello 5',
   
6=>'hello 6',
   
7=>'hello 7',
   
8=>'hello 8'
);
print_r( array_slice($test,2,5) );
?>
Will print:
Array
(
    [0] => hello 3
    [1] => hello 4
    [2] => hello 5
    [3] => hello 6
    [4] => hello 7
)
info [at] saiptek.com
2 years ago
Here is analog to this function. Hope that it helps

function filter_array($input_array, $filter_from, $filter_to)
        {        
            $output_array = array();
           
            foreach ($input_array as $key => $value)
            {
                if($key>=$filter_from && $key<=$filter_to)
                {
                    $output_array[] = $value;
                }
                elseif ($key>$filter_to)
                {
                    //if the key is larger than what we want to filter
                    //it is useless to continue looping
                    break;
                }
                else
                {
                    //if the key is smaller than what we expect
                    continue;
                }
               
            }
           
            return $output_array;
        }

// you can add more security defenses for the variables - e.g. if it is string or something like that
cpa at NOSPAM dot conceptivator dot com
8 years ago
'gportlock at gembiz dot co dot uk' has an error in his limitText function. It simply takes a text string, then cuts off the first X words and returns the rest of the string. I believe the intended use is to return only the first X words and cut off the rest.

The correct version should be (notice the inserted 0 offset):
<?php
function limitText( $text, $wordCount )
{
   
$wordArray = explode(" ", $text);
   
array_splice($wordArray, 0, $wordCount);
    return
implode( " ", $wordArray );
}
?>
aflavio at gmail dot com
9 years ago
/**
    * Remove a value from a array
    * @param string $val
    * @param array $arr
    * @return array $array_remval
    */
    function array_remval($val, &$arr)
    {
          $array_remval = $arr;
          for($x=0;$x<count($array_remval);$x++)
          {
              $i=array_search($val,$array_remval);
              if (is_numeric($i)) {
                  $array_temp  = array_slice($array_remval, 0, $i );
                $array_temp2 = array_slice($array_remval, $i+1, count($array_remval)-1 );
                $array_remval = array_merge($array_temp, $array_temp2);
              }
          }
          return $array_remval;
    }

$stack=Array('apple','banana','pear','apple', 'cherry', 'apple');
array_remval("apple", $stack);

//output: Array('banana','pear', 'cherry')
jamie at jamiechong dot ca
6 years ago
A flexible array_split function:

<?php
// split the given array into n number of pieces
function array_split($array, $pieces=2)
{  
    if (
$pieces < 2)
        return array(
$array);
   
$newCount = ceil(count($array)/$pieces);
   
$a = array_slice($array, 0, $newCount);
   
$b = array_split(array_slice($array, $newCount), $pieces-1);
    return
array_merge(array($a),$b);
}

// Examples:
$a = array(1,2,3,4,5,6,7,8,9,10);
array_split($a, 2);    // array(array(1,2,3,4,5), array(6,7,8,9,10))
array_split($a, 3);    // array(array(1,2,3,4), array(5,6,7), array(8,9,10))
array_split($a, 4);    // array(array(1,2,3), array(4,5,6), array(7,8), array(9,10))

?>
aexchecker at yahoo dot com
8 years ago
<?php
/**
* @desc
* Combines two arrays by inserting one into the other at a given position then
* returns the result.
*
* @since   2007/10/04
* @version v0.7 2007/10/04 18:47:52
* @author  AexChecker <AexChecker@yahoo.com>
* @param   array $source
* @param   array $destination
* @param   int [optional] $offset
* @param   int [optional] $length
* @return  array
*/
function array_insert($source, $destination, $offset = NULL, $length = NULL) {
    if (!
is_array($source) || empty($source)) {
        if (
is_array($destination) && !empty($destination)) {
            return
$destination;
        }
        return array();
    }
    if (
is_null($offset)) {
        return
array_merge($destination, $source);
    }
   
$offset = var2int($offset);
    if (
is_null($length)) {
        if (
$offset === 0) {
            return
array_merge($source, array_slice($destination, 1));
        }
        if (
$offset === -1) {
            return
array_merge(array_slice($destination, 0, -1), $source);
        }
        return
array_merge(
           
array_slice($destination, 0, $offset),
           
$source,
           
array_slice($destination, ++$offset)
        );
    }
    if (
$offset === 0) {
        return
array_merge($source, array_slice($destination, $length));
    }
   
$destination_count = count($destination);
   
$length = var2int($length);
    if (
$offset > 0) {
        if (
$destination_count - $offset < 1) {
            return
array_merge($destination, $source);
        }
    } else{
        if ((
$t = $destination_count + $offset) < 1) {
            return
array_merge($source, $destination);
        }
       
$offset = $t;
    }
    if (
$length > 0) {
       
$length+= $offset;
    } elseif (
$length < 0 && !($length * -1 < $destination_count)) {
        return
$source;
    } else {
       
$length = $offset;
    }
    return
array_merge(
       
array_slice($destination, 0, $offset),
       
$source,
       
array_slice($destination, $length)
    );
}
?>
delew
5 years ago
just a little tip.
to preserve keys without providing length: use NULL

array_slice($array, $my_offset, NULL, true);
jamon at clearsightdesign dot com
7 years ago
I was trying to find a good way to find the previous several and next several results from an array created in a MySQL query. I found that most MySQL solutions to this problem were complex. Here is a simple function that returns the previous and next rows from the array.

<?php

/*
** function array_surround by Jamon Holmgren of ClearSight Design
** Version 1.0 - 4/10/2009
** Please direct comments and questions to my first name at symbol clearsightdesign.com
**
** Returns an array with only the $before and $after number of results
** This is set to work best with MySQL data results
** Use this to find the rows immediately before and after a particular row, as many as you want
**
** Example usage:
**   $mysql_ar is an array of results from a MySQL query and the current id is $cur_id
**   We want to get the row before this one and five rows afterward
**
** $near_rows = array_surround($mysql_ar, "id", $cur_id, 1, 5)
**
**   Previous row is now $near_rows[-1]
**   Current row is now $near_rows[0]
**   Next row is $near_rows[1] ... etc
**   If there is no previous row, $near_rows[-1] will not be set...test for it with is_array($near_rows[-1])
**
*/
function array_surround($src_array, $field, $value, $before = 1, $after = 1) {
    if(
is_array($src_array)) {
       
// reset all the keys to 0 through whatever in case they aren't sequential
       
$new_array = array_values($src_array);
       
// now loop through and find the key in array that matches the criteria in $field and $value
       
foreach($new_array as $k => $s) {
            if(
$s[$field] == $value) {
               
// Found the one we wanted
               
$ck = $k; // put the key in the $ck (current key)
               
break;
            }
        }
        if(isset(
$ck)) { // Found it!
           
$result_start = $ck - $before; // Set the start key
           
$result_length = $before + 1 + $after; // Set the number of keys to return
           
if($result_start < 0) { // Oops, start key is before first result
               
$result_length = $result_length + $result_start; // Reduce the number of keys to return
               
$result_start = 0; // Set the start key to the first result
           
}
           
$result_temp = array_slice($new_array, $result_start, $result_length); // Slice out the results we want
            // Now we have an array, but we want array[-$before] to array[$after] not 0 to whatever.
           
foreach($result_temp as $rk => $rt) { // set all the keys to -$before to +$after
               
$result[$result_start - $ck + $rk] = $rt;
            }
            return
$result;
        } else {
// didn't find it!
           
return false;
        }
    } else {
// They didn't send an array
       
return false;
    }
}

?>

I hope you find this useful! I welcome constructive criticism or comments or of course praise ;) -- just e-mail me.

- Jamon Holmgren
andreasblixt (at) msn (dot) com
10 years ago
<?php
   
// Combines two arrays by inserting one into the other at a given position then returns the result
   
function array_insert($src, $dest, $pos) {
        if (!
is_array($src) || !is_array($dest) || $pos <= 0) return FALSE;
        return
array_merge(array_slice($dest, 0, $pos), $src, array_slice($dest, $pos));
    }
?>
kansey
8 months ago
To save the sort order of a numeric index in the array. Version php =>5.5.26
/*
Example
*/

$arr = array( "1" =>2, "2" =>3 , "3" =>5 );

print_r(array_slice($arr,1,null,true));

/*
Result

Array
(
[2] => 3
[3] => 5
)
*/
Mr. P
7 years ago
Note that offset is not the same thing as key. Offset always starts at 0, while keys might be any number.

So this:

<?php print_r(array_slice(array(0 => 0, 5 => 5, 13 => 13),1)); ?>

will result in this:
Array
(
    [0] => 5
    [1] => 13
)
Anonymous
9 years ago
I noticed that some other people made supportive functions for maintaining numeric keys for PHP versions less than 5.0.2. So here is my version of it.

<?php

//Slice an array but keep numeric keys
function narray_slice($array, $offset, $length) {
   
   
//Check if this version already supports it
   
if (str_replace('.', '', PHP_VERSION) >= 502)
       return
array_slice($array, $offset, $length, true);
       
    foreach (
$array as $key => $value) {
   
        if (
$a >= $offset && $a - $offset <= $length)
           
$output_array[$key] = $value;
       
$a++;
       
    }
   
    return
$output_array;

}

?>
Anonymous
9 years ago
The version check on "ps at b1g dot de" function fails on my copy of PHP.  My Version of PHP is "4.3.10-18", and it ends up checking 4310 <=> 502.
Since we are looking for a version over 4.1.0, we cas use version_compare.
 
<?php
   
// PHP >= 5.0.2 is able to do this itself
   
if(function_exists('version_compare') and version_compare(PHP_VERSION, '5.0.2') >= 0) {
      return
array_slice($array, $offset, $length, true);
    }
?>
fanfatal at fanfatal dot pl
10 years ago
Hmm ... i wrote an usefull function whitch is such like strpos but it works on arrays ;]

<?php
/*
*    Find position of first occurrence of a array
*
*    @param array $haystack
*    @param array $needle
*    @return int
*    @author FanFataL
*/
function array_pos($haystack, $needle) {
   
$size = count($needle);
   
$sizeh = count($haystack);
    if(
$size > $sizeh) return false;

   
$scale = $sizeh - $size + 1;

    for(
$i = 0; $i < $scale; $i++)
        if(
$needle === array_slice($haystack, $i, $size))
            return
$i;

    return
false;
}

// Sample:
$a = array('aa','bb','cc','dd','ee');
$b = array('cc','dd');
$pos = array_pos($a, $b);
?>

Greatings ;-)
...
pies at sputnik dot pl
11 years ago
My shot at Dams's array_slice_key() implementation:

function array_slice_key($array, $offset, $len=-1){

    if (!is_array($array))
        return FALSE;

    $length = $len >= 0? $len: count($array);
    $keys = array_slice(array_keys($array), $offset, $length);
    foreach($keys as $key) {
        $return[$key] = $array[$key];
    }
 
    return $return;
}
jenny at jennys dot info
12 years ago
Here's a function which returns the array offset based on the array key.  This is useful if you'd like to use array_slice to get all keys/values after key "foo".

<?
function array_offset($array, $offset_key) {
  $offset = 0;
  foreach($array as $key=>$val) {
    if($key == $offset_key)
      return $offset;
    $offset++;
  }
  return -1;
}

$array = array('foo'=>'foo', 'bar'=>'bar', 'bash'=>'bash', 'quux'=>'quux');
print_r($array);
// Prints the following:
// Array
// (
//     [foo] => foo
//     [bar] => bar
//     [bash] => bash
//     [quux] => quux
// )

$offset = array_offset($array,'bar');
// $offset now contains '1'
$new = array_slice($array,$offset+1);
print_r($new);
// Prints the following:
// Array
// (
//     [bash] => bash
//     [quux] => quux
// )
?>
joel dot a dot villarreal at gmail dot com
5 years ago
An implementation of array_slice that do not resets the cursor.

<?php
function get_from_array($arr, $start, $length)
{
   
$sliced = array();
    foreach (
$arr as $k => $v)
    {
        if (
$start <= $k && $k <= $start + $length - 1)
        {
           
$sliced[] = $v;
            if (
count($sliced) == $length) break; 
        }
    }
    return
$sliced;
}
?>

Cheers,
Joel A. Villarreal Bertoldi
gary at wits dot sg
4 years ago
I've found this useful.
The following is a function used to shuffle a very specific part of the array, by providing start and end index.

<?php
function array_shuffle_section(&$a, $s, $e) {
   
$head = array_slice($a, 0, $s);
   
$body = array_slice($a, $s, $e-$s+1);
   
$tail = array_slice($a, $e+1);

   
shuffle($body);
   
$a = array_merge($head,$body,$tail);
}
?>
yuwas at ht dot cx
6 years ago
By combining this with str_split() and implode(),slices can also be excerpted from strings with the following simple function:
<?php
function str_slice($string,$offset,$length=999,$preserve_keys=False){
  if(
$length == 999 ){ $length = strlen($string)-$offset };
 
$slice_arr = array_slice(str_split($string),$offset,$length,$preserve_keys);
  return
implode($slice_arr);
};
?>

Perhaps there's a better way to preset $length.
ted.devito at 9gmail9 dot 99com
7 years ago
based on worldclimb's arem(), here is a recursive array value removal tool that can work with multidimensional arrays.

function remove_from_array($array,$value){
    $clear = true;
    $holding=array();
  
    foreach($array as $k => $v){
        if (is_array($v)) {
            $holding [$k] = remove_from_array ($v, $value);
            }
        elseif ($value == $v) {
            $clear = false;
            }
        elseif($value != $v){
            $holding[$k]=$v; // removes an item by combing through the array in order and saving the good stuff
        }
    }  
    if ($clear) return $holding; // only pass back the holding array if we didn't find the value
}
gportlock at gembiz dot co dot uk
8 years ago
This function returns a text string that is limited by the word count. This funtion is particularly useful for paid advertising where you pay by the word.

function limitText( $text, $wordCount ){

        $wordArray = explode(" ", $text);
        array_splice($wordArray, $wordCount);
        return implode( " ", $wordArray );
}
ps at b1g dot de
9 years ago
The following function is the same as array_slice with preserve_keys=true, but it works with PHP versions < 5.0.2.
When PHP >= 5.0.2 is available, the function uses the faster PHP-own array_slice-function with preserve_keys=true, otherwise it uses its own  implementation.

<?php
/**
* array_slice with preserve_keys for every php version
*
* @param array $array Input array
* @param int $offset Start offset
* @param int $length Length
* @return array
*/
function array_slice_preserve_keys($array, $offset, $length = null)
{
   
// PHP >= 5.0.2 is able to do this itself
   
if((int)str_replace('.', '', phpversion()) >= 502)
        return(
array_slice($array, $offset, $length, true));

   
// prepare input variables
   
$result = array();
   
$i = 0;
    if(
$offset < 0)
       
$offset = count($array) + $offset;
    if(
$length > 0)
       
$endOffset = $offset + $length;
    else if(
$length < 0)
       
$endOffset = count($array) + $length;
    else
       
$endOffset = count($array);
   
   
// collect elements
   
foreach($array as $key=>$value)
    {
        if(
$i >= $offset && $i < $endOffset)
           
$result[$key] = $value;
       
$i++;
    }
   
   
// return
   
return($result);
}
?>

Good for backwards compatibility I hope somebody might find this useful.
ssb45 at cornell dot edu
10 years ago
In reply to jenny at jennys dot info:

Here is a much easier way to find the $offset of a $key in an $array:

$offset = array_search($key, array_keys($array));
liz at matrixmailing dot com
10 years ago
For those with PHP < 5.0.2, and have a number as your array key, to avoid having the key reset with array_slice, add a blank character to the beginning or end of the key.
<?

$array[" ".$key] = $value;

?>
bishop
11 years ago
Sometimes you need to pick certain non-integer and/or non-sequential keys out of an array. Consider using the array_pick() implementation below to pull specific keys, in a specific order, out of a source array:

<?php

$a
= array ('a' => 1, 'b' => 2, 'c' => 3, 'd' => 4);
$b = array_pick($a, array ('d', 'b'));

// now:
// $a = array ('a' => 1, 'c' => '3');
// $b = array ('d' => 4, 'b' => '2');

function &array_pick(&$array, $keys)
{
    if (!
is_array($array)) {
       
trigger_error('First parameter must be an array', E_USER_ERROR);
        return
false;
    }

    if (! (
is_array($keys) || is_scalar($keys))) {
       
trigger_error('Second parameter must be an array of keys or a scalar key', E_USER_ERROR);
        return
false;
    }

    if (
is_array($keys)) {
       
// nothing to do
   
} else if (is_scalar($keys)) {
       
$keys = array ($keys);
    }

   
$resultArray = array ();
    foreach (
$keys as $key) {
        if (
is_scalar($key)) {
            if (
array_key_exists($key, $array)) {
               
$resultArray[$key] = $array[$key];
                unset(
$array[$key]);
            }
        } else {
           
trigger_error('Supplied key is not scalar', E_USER_ERROR);
            return
false;
        }
    }

    return
$resultArray;
}

?>
Samuele at norsam dot org
12 years ago
Note that if $offset+$length>count($array) then resulting array will NOT be filled with empty elements at his end, so it is not sure that it will have exactly $length elements. Example:
<?php
$a
=Array(7,32,11,24,65); // count($a) is 5
$b=array_slice($a,2,4);  // 2+4=6, and 6>count($a)
print_r($b);
?>
will return a 3-elements array:
  Array
  (
      [0] => 11
      [1] => 24
      [2] => 65
  )
Anonymous
12 years ago
Use unset() to delete a associative array.

Ex:
<?php
                                                                                                                              
$item
['chaise'] = array ('qty' => 1,
                       
'desc' => 'Chaise bercante 10"',
                       
'avail' => 10);
                                                                                                                              
$item['divan'] = array ('qty' => 1,
                       
'desc' => 'Divan brun laitte"',
                       
'avail' => 10);
                                                                                                                              
if (isset(
$item['chaise'])) {
        ++
$item['chaise']['qty'];
        }
                                                                                                                              
unset(
$item['divan']);
                                                                                                                              
foreach (
$item as $s) {
        echo
"<br />Commande " . $s['qty'] . " " . $s['desc'];
}
                                                                                                                              
?>
richardgere at jippii dot fi
14 years ago
The same thing, written by a maladroit :)

<?php
function array_slice2( $array, $offset, $length = 0 )
{
  if(
$offset < 0 )
   
$offset = sizeof( $array ) + $offset;

 
$length = ( !$length ? sizeof( $array ) : ( $length < 0 ? sizeof( $array ) - $length : $length + $offset ) );

  for(
$i = $offset; $i < $length; $i++ )
   
$tmp[] = $array[$i];

  return
$tmp;     
}
?>
t dot oddy at ic dot ac dot uk
14 years ago
[Editor's Note:
It is easier to do the same thing using array_values()
]
array_slice() can be used to "re-index" an array to start from key 0.  For example, unpack creates an array with keys starting from 1;

<?php
var_dump
(unpack("C*","AB"));
?>

produces

<?php
array(2) {
  [
1]=>
 
int(65)
  [
2]=>
 
int(66)
}
?>

and

<?php
var_dump
(array_slice(unpack("C*","AB"),0));
?>

give you

<?php
array(2) {
  [
0]=>
 
int(65)
  [
1]=>
 
int(66)
}
?>
fraterjan at gmail dot com
1 year ago
To make sure numerical key values for associative arrays are not converted to integers set $preserve_keys = true.

Example:
$slice = array_slice($array, 0, 3, $preserve_keys = true);
phpnotasp at gmail dot com
8 years ago
It should be noted that this function does NOT modify the original array. So if you need to array_pop() or array_shift() without modifying the original array, you can use array_slice().

<?php

$input
= array('a', 'b', 'c');
$output = array_slice($input, 1);

print_r($output);
print_r($input);

/*
Array
(
    [0] => b
    [1] => c
)
Array
(
    [0] => a
    [1] => b
    [2] => c
)
*/
?>
david at bagnara dot org
9 years ago
I was trying to pass an argument list through the constructors. I tried various things such as func_get_args(). My conclusion is to pass the args to the constructor as an array. Each constructor can remove the fields it wants and pass the array on.

Using the following prototype, each child class can have any number of parameters added to the beginning of the class constructor and the rest passed onto the parent.

If the default value is desired for an argument, just pass NULL.

This could possibly be better done with array_shift or the like.

<?php

class aChild extends aParent
{
   
// TODO customise this list for this class
   
public
       
$a, $b, $c;

    function
__construct( $args = array() )
    {
       
//set up default values for this class
        // TODO customise this list for this class
       
$default = array( "a-def", "b-def", "c-def" ) ;
       
// now overwrite the default with non NULL args
       
foreach( $args as $key=>$val )
        {
           
// more args than needed?
           
if( !isset( $default[$key] ) )
            {
                break;
            }
           
// this arg not null
           
if( isset( $val ) )
            {
               
$default[$key] = $val ;
            }
        }
       
// set this to the new values
        // TODO customise this list for this class
       
list( $this->a, $this->b, $this->c ) = $default ;
       
// take off the ones we used
       
$args = array_slice( $args, count( $default ) ) ;
       
parent::__construct( $args ) ;
    }
}

$x = new aChild( array( "aChild a", NULL, "aChild c", NULL, "aParent second", "aParent third" ) ) ;
?>
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