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array_values> <array_unique
Last updated: Sun, 25 Nov 2007

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array_unshift

(PHP 4, PHP 5)

array_unshift — 배열의 맨 앞에 하나 이상의 원소를 첨가한다

설명

int array_unshift ( array $array , mixed $var [, mixed $ ... ] )

array_unshift()는 전달된 원소들을 array 의 앞에 첨가한다. 원소 목록이 모두 첨가되면, 첨가된 원소들은 같은 순서로 남아있게 된다는 것에 유의한다. 모든 숫자 배열 키들은 리터럴 키들이 건드러지지 않는 동안에는 제로부터 카운트를 시작할수 있도록 변경될것이다.

array 안의 새로운 원소의 수를 반환한다.

Example#1 array_unshift() 예제코드

<?php
$queue 
= array ("orange""banana");
array_unshift ($queue"apple""raspberry");
?>

위 코드는 다음 원소를 갖는 $queue 결과를 갖는다:

Array
(
    [0] => apple
    [1] => raspberry
    [2] => orange
    [3] => banana
)

array_shift(), array_push(), array_pop() 참고.



array_values> <array_unique
Last updated: Sun, 25 Nov 2007
 
add a note add a note User Contributed Notes
array_unshift
Rafael M. Salvioni
12-Jun-2008 09:52
This function inserts a element in any position of the Array, by reference.

NOTE: The array is converted for a numeric array.

<?php

/**
 * Function array_insert().
 *
 * Returns the new number of the elements in the array.
 *
 * @param array $array Array (by reference)
 * @param mixed $value New element
 * @param int $offset Position
 * @return int
 */
function array_insert(&$array, $value, $offset)
{
    if (
is_array($array)) {
       
$array  = array_values($array);
       
$offset = intval($offset);
        if (
$offset < 0 || $offset >= count($array)) {
           
array_push($array, $value);
        } elseif (
$offset == 0) {
           
array_unshift($array, $value);
        } else {
           
$temp  = array_slice($array, 0, $offset);
           
array_push($temp, $value);
           
$array = array_slice($array, $offset);
           
$array = array_merge($temp, $array);
        }
    } else {
       
$array = array($value);
    }
    return
count($array);
}

?>
sergei at gmx dot net
03-Oct-2007 08:49
You can preserve keys and unshift an array with numerical indexes in a really simple way if you'll do the following:

$someArray=array(224=>'someword1', 228=>'someword2', 102=>'someword3', 544=>'someword3',95=>'someword4');

$someArray=array(100=>'Test Element 1 ',255=>'Test Element 2')+$someArray;

now the array looks as follows:

array(
100=>'Test Element 1 ',
255=>'Test Element 2'
224=>'someword1',
228=>'someword2',
102=>'someword3',
544=>'someword3',
95=>'someword4'
);
mightye at gmail dot com
10-Aug-2007 05:38
@John Brooking:
Better performing would most likely be array_values($input)
amschroeder at gmail dot com
26-Mar-2007 10:13
This becomes a nice little problem if you index your arrays out of order (while manually sorting).  For example:

$recordMonths[3] = '8/%/2006';
$recordMonths[4] = '7/%/2004';
$recordMonths[0] = '3/%/2007';
$recordMonths[1] = '2/%/2007';
$recordMonths[5] = '12/%/2000';
$recordMonths[6] = '11/%/2000';
$recordMonths[7] = '10/%/2000';
$recordMonths[2] = '1/%/2007';

for($i = 0; $i < count($recordMonths); $i++)
{
    $singleMonth = $recordMonths[$i];
    echo "singleMonth: $singleMonth <br />";
}
array_unshift($recordMonths,'%');
for($i = 0; $i < count($recordMonths); $i++)
{
    $singleMonth = $recordMonths[$i];
    echo "singleMonth: $singleMonth <br />";
}

Produces:

singleMonth: 3/%/2007
singleMonth: 2/%/2007
singleMonth: 1/%/2007
singleMonth: 8/%/2006
singleMonth: 7/%/2004
singleMonth: 12/%/2000
singleMonth: 11/%/2000
singleMonth: 10/%/2000
singleMonth: %
singleMonth: 8/%/2006
singleMonth: 7/%/2004
singleMonth: 3/%/2007
singleMonth: 2/%/2007
singleMonth: 12/%/2000
singleMonth: 11/%/2000
singleMonth: 10/%/2000
singleMonth: 1/%/2007

It reindexes them based on the order they were created.  It seems like if an array has all numeric indexes, then it should reindex them based on the order of their index.  Just my opinion...
John Brooking
02-Jun-2006 06:54
I had a need tonight to convert a numeric array from 1-based to 0-based, and found that the following worked just fine due to the "side effect" of renumbering:

   array_unshift( $myArray, array_shift( $myArray ));
06-Nov-2005 11:38
function multi_array_search($search_value, $the_array)
{
   if (is_array($the_array))
   {
       foreach ($the_array as $key => $value)
       {
           $result = multi_array_search($search_value, $value);
           if (is_array($result))
           {
               $return = $result;
               array_unshift($return, $key);
               return $return;
           }
           elseif ($result == true)
           {
               $return[] = $key;
               return $return;
           }
       }
       return false;
   }
   else
   {
       if ($search_value == $the_array)
       {
           return true;
       }
       else return false;
   }
}
php at electricsurfer dot com
26-Feb-2004 06:20
even simpler unshifting of a reference !
<?php
/**
 * @return int
 * @param $array array
 * @param $value mixed
 * @desc Prepend a reference to an element to the beginning of an array. Renumbers numeric keys, so $value is always inserted to $array[0]
 */
function array_unshift_ref(&$array, &$value)
{
  
$return = array_unshift($array,'');
  
$array[0] =& $value;
   return
$return;
}
?>
lagroue
09-Nov-2003 04:46
Last version of PHP deprecated unshifting of a reference.
You can use this function instead :

<?php
function array_unshift1 (& $ioArray, $iValueWrappedInAnArray) {
   
$lNewArray = false;
    foreach (
array_keys ($ioArray) as $lKey)
       
$lNewArray[$lKey+1] = & $ioArray[$lKey];
   
$ioArray = array (& $iValueWrappedInAnArray[0]);
    if (
$lNewArray)
        foreach (
array_keys ($lNewArray) as $lKey)
            
$ioArray[] = & $lNewArray[$lKey];
    return
count($ioArray);
}

// before last PHP (now generates a deprecation warning)
array_unshift ($a, &$v);
// since last PHP (caution, there is a wrapping array !!)
array_unshift1 ($a, array (&$v));
?>
chris dot NoThxSpam dot given at hp dot com
23-Jul-2003 12:17
If you need to change the name of a key without changing its position in the array this function may be useful.

<?php
function array_key_change($Old, $New, $In, $NewVal=NULL) {
       
$Temp = array();
        while(isset(
$Temp[$Old]) == false) {
                list(
$k, $v) = each($In);
               
$Temp[$k] = $v;
                unset(
$In[$k]);
        }
        if(
$NewVal == NULL) {
               
$NewVal = $Temp[$Old];
        }
        unset(
$Temp[$Old]);
       
$Temp = array_reverse($Temp);
       
$In = array_merge(array($New=>$NewVal), $In);
        while(list(
$k,$v) = each($Temp)) {
               
$In = array_merge(array($k=>$v), $In);
        }
        return(
$In);
}
?>
rsmith_NOSPAM_ at _NOSPAM_unitec dot ac dot nz
30-Jul-2002 07:00
array_merge() will also reindex (see array_merge() manual entry), but the '+' operator won't, so...

<?php
$arrayone
=array("newkey"=>"newvalue") + $arrayone;
?>

does the job.
TimHyde at C21Technology dot com
18-Jul-2002 05:04
A simpler way to implement an array_unshift with key=>value pairs (i.e. similar to the example using array_reverse above) is to use array_merge.  i.e.

<?php
$arrayone
=array_merge(array("newkey"=>"newvalue"),$arrayone);
?>

Obviously you need to take care when adding numeric or duplicate keys.
jrh_at_geodata.soton.ac.uk
10-Jul-2002 09:30
I have found array_unshift is a function that should be avoided when unshifting lots of data in large arrays.

In a recent script I wrote, it took approx. 24 seconds to unshift 3500 timestamps to an array, a work around could be to use array_reverse and array_push. Array_push is much faster due to the indexing.
robert dot wills at fuzzbrain dot uklinux dot net
07-Feb-2002 06:02
Actually this problem with the keys getting reindexed only happens when the keys are numerical:

<?php

$a
= array("f"=>"five", "s" =>"six", "t" =>
       
"twenty");

print_r($a);
echo
"\n";
foreach(
$a as $key=>$val)
{
    echo
"k: $key v: $val \n";
}

array_unshift($a, "zero");
print_r($a);
echo
"\n";
foreach(
$a as $key=>$val)
{
    echo
"k: $key v: $val \n";
}
?>

Array
(
    [f] => five
    [s] => six
    [t] => twenty
)

k: f v: five
k: s v: six
k: t v: twenty
Array
(
    [0] => zero
    [f] => five
    [s] => six
    [t] => twenty
)

k: 0 v: zero
k: f v: five
k: s v: six
k: t v: twenty
sahn at hmc dot edu
27-Jul-2001 12:21
If you need to prepend something to the array without the keys being reindexed and/or need to prepend a key value pair, you can use this short function:

<?php
function array_unshift_assoc(&$arr, $key, $val)
{
   
$arr = array_reverse($arr, true);
   
$arr[$key] = $val;
   
$arr = array_reverse($arr, true);
    return
count($arr);
}
?>
matt at synergie dot net
18-Sep-2000 10:20
The behaviour of unshift nearly caught me out.
Not only is the item added at the start of the list but the list is re-indexed too.

<?php

$a
= array(5=>"five", 6 =>"six", 20 => "twenty");

while(list(
$key, $value) = each($a))
    echo
"k: $key v: $value<BR>\n";

echo
"<BR>\n";
array_unshift($a, "zero");


while(list(
$key, $value) = each($a))
    echo
"k: $key v: $value<BR>\n";

?>

k: 5 v: five
k: 6 v: six
k: 20 v: twenty

k: 0 v: zero
k: 1 v: five
k: 2 v: six
k: 3 v: twenty

array_values> <array_unique
Last updated: Sun, 25 Nov 2007
 
 
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