array_unique
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'
);
array_unshift
(PHP 4, PHP 5)
array_unshift — Fügt ein oder mehr Elemente am Anfang eines Arrays ein
Beschreibung
array_unshift() fügt die übergebenen Elemente am Anfang von array ein. Beachten Sie, dass die Liste von Elementen als Ganzes eingefügt wird, sodass die eingefügten Elemente die selbe Reihenfolge haben. Die numerischen Schlüssel werden so modifiziert, dass bei null zu zählen begonnen wird, Strings als Schlüssel bleiben unverändert.
Diese Funktion gibt die neue Anzahl der in array enthaltenen Elemente zurück.
Beispiel #1 array_unshift()
<?php
$queue = array("Orange", "Banane");
array_unshift($queue, "Apfel", "Himbeere");
?>
Als Ergebnis enthält $queue die folgenden Elemente:
Array ( [0] => Apfel [1] => Himbeere [2] => Orange [3] => Banane )
Siehe auch array_shift(), array_push() und array_pop().
add a note
User Contributed Notesarray_unshift
sergei at gmx dot net
03-Oct-2007 08:49
03-Oct-2007 08:49
mightye at gmail dot com
10-Aug-2007 05:38
10-Aug-2007 05:38
@John Brooking:
Better performing would most likely be array_values($input)
amschroeder at gmail dot com
26-Mar-2007 10:13
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
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
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
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 (&$v));
?>
chris dot NoThxSpam dot given at hp dot com
23-Jul-2003 12:17
23-Jul-2003 12:17
If you need to change the name of a key without changing its position in the array this function may be useful.
<?php
function array_key_change($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
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
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
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
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: $val \n";
}
?>
Array
(
[f] => five
[s] => six
[t] => twenty
)
k: f v: five
k: s v: six
k: t v: twenty
Array
(
[0] => zero
[f] => five
[s] => six
[t] => twenty
)
k: 0 v: zero
k: f v: five
k: s v: six
k: t v: twenty
sahn at hmc dot edu
27-Jul-2001 12:21
27-Jul-2001 12:21
If you need to prepend something to the array without the keys being reindexed and/or need to prepend a key value pair, you can use this short function:
<?php
function array_unshift_assoc(&$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
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