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(PHP 5)
array_combine — Erzeugt ein Array, indem es ein Array für die Schlüsel und ein anderes für die Werte verwendet
Erzeugt ein Array, in dem die Werte des keys-Arrays als Schlüssel und die Werte aus dem values-Array als die zugehörigen Werte verwendet werden.
Array mit den zu verwendenden Schlüsseln. Für Schlüssel ungültige Werte werden in einen String umgewandelt.
Array mit den zu verwendenden Werten
Gibt das kombinierte Array oder FALSE zurück, wenn die Anzahl von Elementen nicht in beiden Arrays identisch ist oder die Arrays leer sind.
Wirft einen Fehler der Stufe E_WARNING, wenn keys und values entweder leer sind oder die Anzahl der Elemente nicht übereinstimmt.
Beispiel #1 Ein einfaches array_combine()-Beispiel
<?php
$a = array('gruen', 'rot', 'gelb');
$b = array('avokado', 'apfel', 'banane');
$c = array_combine($a, $b);
print_r($c);
?>
Das oben gezeigte Beispiel erzeugt folgende Ausgabe:
Array
(
[gruen] => avokado
[rot] => apfel
[gelb] => banane
)
array_combine() has a strange bug/misfeature (as of PHP 5.3.2): There is no logical reason for <? array_combine(array(), array()) ?> throwing a warning and returning FALSE, instead of returning <? array() ?> (see http://bugs.php.net/bug.php?id=34857). Here is a quick workaround:
<?php
function array_real_combine($a, $b)
{
return $a===array() && $b===array() ? array() : array_combine($a, $b);
}
?>
I needed a function that would take keys from one unequal array and combine them with the values of another. Real life application:
Select 4 product types.
Each product has a serial.
There are 4 sets of products.
<?php
function array_combine2($arr1, $arr2) {
$count1 = count($arr1);
$count2 = count($arr2);
$numofloops = $count2/$count1;
$i = 0;
while($i < $numofloops){
$arr3 = array_slice($arr2, $count1*$i, $count1);
$arr4[] = array_combine($arr1,$arr3);
$i++;
}
return $arr4;
}
?>
Input:
Array
(
[0] => SMART Board
[1] => Projector
[2] => Speakers
[3] => Splitter
)
, Array
(
[0] => serial to smart board1
[1] => serial to projector 1
[2] => serial to speakers 1
[3] => serials to splitter 1
[4] => serials to smart board 2
[5] => serials to projector 2
[6] => serials to speakers 2
[7] => serials to splitter 2
)
Array
(
[0] => Array
(
[SMART Board] => serial to smart board1
[Projector] => serial to projector 1
[Speakers] => serial to speakers 1
[Splitter] => serials to splitter 1
)
[1] => Array
(
[SMART Board] => serials to smart board 2
[Projector] => serials to projector 2
[Speakers] => serials to speakers 2
[Splitter] => serials to splitter 2
)
)
<?php
/**
* Return alternatives defined by values of each parameters.
*
* Exemple :
*
* array_alternatives(array('foo','bar'), array('baz', 'qux'));
* array(
* array('foo', 'baz'),
* array('bar', 'baz'),
* array('foo', 'qux'),
* array('bar', 'qux'),
* );
*
* array_alternatives(array('a'), array('simple-minded'), array('solution'));
* array(
* array('a', 'simple-minded', 'solution')
* );
*
* array_alternatives(array('a'), array('red', 'blue'), array('car'));
* array(
* array('a', 'red', 'car'),
* array('a', 'blue', 'car'),
* );
*
* @param array $first_element
* @param array $second_element
* @return array
* @author Xavier Barbosa
*/
function array_alternatives(array $first_element, array $second_element)
{
$lists = func_get_args();
$total_lists = func_num_args();
for($i=0; $i<$total_lists; $i++)
{
$list =& $lists[$i];
if (is_array($list) === FALSE)
throw new Exception("Parameter $i is not an array.");
if (count($list) === 0)
throw new Exception("Parameter $i has no element.");
unset($list);
}
// Initialize our alternatives
$alternatives = array();
foreach($lists[0] as &$value)
{
array_push($alternatives, array($value));
unset($value);
}
unset($lists[0]);
// Process alternatives
for($i=1; $i<$total_lists; $i++)
{
$list =& $lists[$i];
$new_alternatives = array();
foreach($list as &$value)
{
foreach($alternatives as $_)
{
array_push($_, $value);
array_push($new_alternatives, $_);
}
}
// Rotate references, it's cheaper than copy array like `$alternatives = $new_alternatives;`
$alternatives =& $new_alternatives;
unset($new_alternatives, $list, $lists[$i]);
}
return $alternatives;
}
?>
<?php
// If they are not of same size, here is solution:
$abbreviations = array("AL", "AK", "AZ", "AR", "TX", "CA");
$states = array("Alabama", "Alaska", "Arizona", "Arkansas");
function combine_arr($a, $b)
{
$acount = count($a);
$bcount = count($b);
$size = ($acount > $bcount) ? $bcount : $acount;
$a = array_slice($a, 0, $size);
$b = array_slice($b, 0, $size);
return array_combine($a, $b);
}
$combined = combine_arr($abbreviations, $states);
print_r($combined);
// Output
// Array ( [AL] => Alabama [AK] => Alaska [AZ] => Arizona
// [AR] => Arkansas )
?>
This may be obvious, but I don't see anything about it on the manual page, so a friendly warning... The array you are using as keys must have all unique values. If not, array elements get dropped.
<?php
$arr_notUnique = array('one' , 'one' , 'two');
$arr_b = array('red' , 'green' , 'blue');
$arr_combo = array_combine($arr_notUnique, $arr_b);
?>
Results: Array ( [one] => green [two] => blue )
NOT: Array ( [one] => red [one] => green [two] => blue )
Also, Khalys function only works if keys of both arrays are the same because array_combine ignores keys. An easy way to ignore them is by taking array_values(). Floats can be casted to strings to avoid overwriting.
So, the PHP4 function could look something like this:
<?php
function array_combine($arr1, $arr2) {
$out = array();
$arr1 = array_values($arr1);
$arr2 = array_values($arr2);
foreach($arr1 as $key1 => $value1) {
$out[(string)$value1] = $arr2[$key1];
}
return $out;
}
?>
Khaly's PHP4 code below does not work correctly in all cases. Consider when your array consists of floats:
<?php
$okay = array(0, 10, 20, 30);
$not_okay = array(0, 0.5, 1, 1.5);
$foo = array_combine($okay, $okay);
$bar = array_combine($not_okay, $not_okay);
/*
Results:
$foo = {
[0]=> int(0)
[10]=> int(10)
[20]=> int(20)
[30]=> int(30)
}
$bar = {
[0]=> float(0.5)
[1]=> float(1.5)
}
*/
?>
What can you do? In my case, I was just zipping up some select-box options, so I converted everything in my floats to strings.
This is the function for PHP4 :
<?php
function array_combine($arr1,$arr2) {
$out = array();
foreach($arr1 as $key1 => $value1) {
$out[$value1] = $arr2[$key1];
}
return $out
}
?>
Some tips for merging same values in an array
<?php
$array1 = array(1,2,3,4,5,6,7,8,9,10,11,12);
$array2 = array(1,2,3,13);
$merged = array_merge($array1,$array2);
// output normal array_merge
echo '<pre>After array_merge :
';
print_r($merged);
echo '</pre>';
// do double flip for merging values in an array
$merged = array_flip($merged);
$merged = array_flip($merged);
// Output after
echo '<pre>After Double Flip :
';
print_r($merged);
echo '</pre>';
?>
Output ::
After array_merge :
Array
(
[0] => 1
[1] => 2
[2] => 3
[3] => 4
[4] => 5
[5] => 6
[6] => 7
[7] => 8
[8] => 9
[9] => 10
[10] => 11
[11] => 12
[12] => 1
[13] => 2
[14] => 3
[15] => 13
)
After Double Flip :
Array
(
[12] => 1
[13] => 2
[14] => 3
[3] => 4
[4] => 5
[5] => 6
[6] => 7
[7] => 8
[8] => 9
[9] => 10
[10] => 11
[11] => 12
[15] => 13
)
Use that code to group an array by its first element.
<?
function groupbyfirst($array)
{
foreach ($array as $row)
{
$firstkey = array_keys($row);
$firstkey = $firstkey[0];
$key = $row[$firstkey];
unset($row[$firstkey]);
$newarray[$key][] = $row;
}
return $newarray;
}
?>
Example:
<?
$array =
Array(
0 => Array('color' => 'red','name' => 'apple', 'quantity' => '3'),
1 => Array('color' => 'green','name' => 'pear', 'quantity' => '2'),
2 => Array('color' => 'yellow','name' => 'corn', 'quantity' => '3'),
3 => Array('color' => 'blue','name' => 'grape', 'quantity' => '4'),
4 => Array('color' => 'yellow','name' => 'banana', 'quantity' => '13'),
);
$output = groupbyfirst($array);
print_r($output);
?>
will return:
Array
(
[red] => Array ( [0] => Array ( [name] => apple [quantity] => 3 ) )
[green] => Array ( [0] => Array ( [name] => pear [quantity] => 2 ) )
[yellow] => Array ( [0] => Array ( [name] => corn [quantity] => 3 ), [1] => Array ( [name] => banana [quantity] => 13 ) )
[blue] => Array ( [0] => Array ( [name] => grape [quantity] => 4 ))
)
Or you can use mysql recordset:
<?
while ($row=mysql_fetch_array($result,MYSQL_ASSOC))
{
$firstkey = array_keys($row);
$firstkey = $firstkey[0];
$key = $row[$firstkey];
unset($row[$firstkey]);
$newarray[$key][] = $row;
}
?>
This functionality is now implemented in the PEAR package PHP_Compat.
More information about using this function without upgrading your version of PHP can be found on the below link:
http://pear.php.net/package/PHP_Compat
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