PHP: array_combine

Description

array array_combine ( array keys, array values )

Returns an array by using the values from the keys array as keys and the values from the values array as the corresponding values.

Returns FALSE if the number of elements for each array isn't equal or if the arrays are empty.

Example 1. A simple array_combine() example

<?php $a = array('green', 'red', 'yellow'); $b = array('avocado', 'apple', 'banana'); $c = array_combine($a, $b); print_r($c); ?>
The above example will output:
Array ( [green] => avocado [red] => apple [yellow] => banana )

User Contributed Notes
array_combine

ungu at terong dot com
10-May-2005 01:52


Sorry for the mistype in previous submission, here is the correct one completed with a sample.

Simpler version of array_combine if you do not use PHP 5



<?

if(!function_exists('array_combine')) function array_combine($a, $b) {

    $c = array();

    $at = array_values($a);

    $bt = array_values($b);

    foreach($at as $key=>$aval) $c[$aval] = $bt[$key];

    return $c;

}



$a = array('green', 'red', 'yellow');

$b = array('avocado', 'apple', 'banana');

$c = array_combine($a, $b);



print_r($c);

?>

ungu at terong dot com
10-May-2005 01:39


Simpler version of array_combine if you do not use PHP 5



<?

if (!function_exists('array_combine')) {

    function array_combine($a, $b) {

        $c = array();

        $at = array_values($a);

        $bt = array_values($b);

        foreach($at as $key=>$aval) $c[$aval] = $b[$key];

        return $c;

    }

} 

?>

dreptack at op dot pl
22-Apr-2005 06:15


For those of you want to use this function but have php version < 5.0

<?php

if (!function_exists('array_combine')) {

    //{{{ array_combine

    /**

    * Creates an array by using one array for keys and another for its values

    * @param    array    $keys

    * @param    array    $values

    * @return    Returns an array by using the values from the keys array as keys and the values from the values array as the corresponding values.<br />Returns FALSE if the number of elements for each array isn't equal or if the arrays are empty.

    * @author    <dreptack [at] op [dot] pl>

    */

    function array_combine($keys, $values)

    {

        if (!is_array($keys) || !is_array($values) || !$keys || !$values || count($keys) != count($values)) {

            return false;

        }

        reset($keys);

        reset($values);

        $retarr = array();

        while (($keyarr = each($keys)) && ($valarr = each($values))) {

            $retarr[$keyarr['value']] = $valarr['value'];

        } 

        return $retarr;

    } //}}}

} //endif function_exists

?>

Enjoy:-)

ifeghali at interveritas dot net
26-Feb-2005 12:53


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;

}

?>

aidan at php dot net
20-May-2004 09:15


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