array_combine

(PHP 5)

array_combine — 一方の配列をキーとして、もう一方の配列を値として、ひとつの配列を生成する

説明

array array_combine ( array keys, array values )

keys 配列の値をキーとして、また values 配列の値を対応する値として生成した配列を返します。

互いの配列の要素の数が合致しない場合や空の配列である場合に FALSE を返します。

例 215. array_combine()の簡単な例


<?php

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

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

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



print_r($c);

?>

上の例の出力は以下となります。


Array
(
    [green]  => avocado
    [red]    => apple
    [yellow] => banana
)

array_merge()、 array_walk() および array_values() も参照ください。

add a note User Contributed Notes
array_combine

MSpreij, c/o GMail
10-Sep-2006 05:47


And another one..

<?php

if (! function_exists('array_combine')) {

  function array_combine($keys, $values) {

    foreach($keys as $key) $out[$key] = array_shift($values);

    return $out;

  }

}

?>



If there are less values then keys, the extra values will be NULL (that's what array_shift returns).

glashio.at.gmail.com
07-Dec-2005 07:00


I encounterd a "Fatal Error" on PHP4 while i developed on PHP5 using : array_combine($a, $b);



__TOP_OF_SCRIPT__



if (!function_exists('array_combine')) {

    function array_combine($a, $b) {

        $c = array();

        if (is_array($a) && is_array($b))

            while (list(, $va) = each($a))

                if (list(, $vb) = each($b))

                    $c[$va] = $vb;

                else

                    break 1;

        return $c;

    }

}

m at momech dot dk
02-Nov-2005 12:55


An 3-liner way to get the effect of array_combine in PHP4:

<?php

$keysValues = array();

foreach($csvFieldnames as $indexnum => $key)

    $keyValues[$key] = $values[$indexnum];

?>



/ Mogens

Ivo van Sandick
02-Sep-2005 05:04


Such a useful function, and only since version 5! Why an emulation for earlier PHP versions has not been posted long ago, is a mystery:



<?php

function array_combine_emulated( $keys, $vals ) {

 $keys = array_values( (array) $keys );

 $vals = array_values( (array) $vals );

 $n = max( count( $keys ), count( $vals ) );

 $r = array();

 for( $i=0; $i<$n; $i++ ) {

  $r[ $keys[ $i ] ] = $vals[ $i ];

 }

 return $r;

}

?>

ifeghali at interveritas dot net
27-Feb-2005 03:53


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
21-May-2004 11:15


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

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array_count_values

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array_chunk

Last updated: Mon, 05 Feb 2007