3 Examples of Methods to Convert Multidimensional Arrays to One-Dimensional Arrays in PHP_PHP Tutorial

Many times we need to convert multi-dimensional arrays into one-dimensional arrays, because we only need one-dimensional arrays, and one-dimensional arrays are more convenient to use. How to convert multi-dimensional arrays into one-dimensional arrays in PHP? Let’s take a look at three examples of converting multi-dimensional arrays into one-dimensional arrays:
1. Use foreach

Copy code code As follows:

function arr_foreach ($arr)
{
static $tmp=array();
if (!is_array ($arr))
                                       return false;                                                               arr_foreach ($val) ;
                                                                            > }
$a = array (1,2=>array(3,4=>array(5,6)),7);
print_r(arr_foreach($a));
?>


2. Using a for loop, you can only traverse the array of numerical subscripts




Copy the code

The code is as follows:

< ?php
function arr_foreach($arr)
{

static $tmp=array();
for($i=0; $i                                                                                   $tmp[] =$arr[$i]; } }

} } return $tmp; } //Calling example

$a = array(1,array(3 ,array(5,6)),7);

print_r(arr_foreach($a));
?>


3. Use while




Copy code

The code is as follows:

/**
* Convert multi-dimensional array to one-dimensional array
* @author echo
* @link http://www.jb51.net/
* @param array $arr
* @return array
*/
function ArrMd2Ud($arr) {

#Change the value An element serves as a container for address assignment.
$ar_room = &$arr[key($arr)]; #The first container is not an array. if (!is_array($ar_room)) {
#Convert to an array

$ar_room = array($ar_room); } #Move the pointer down next($arr); #Traverse

while (list($k, $v) = each($arr)) {

#If it is an array, dig deep recursively, if not, convert it to an array
$v = is_array($v) ? call_user_func(__FUNCTION__, $v) : array($v);
#Recursive merge
$ar_room = array_merge_recursive($ar_room, $v);
#Release the array element of the current subscript
unset($arr[$k]);
}
return $ar_room;
}


Call example:



Copy code

The code is as follows:


$arr = array(1, 2, 3 => ; array(1, 2, 'ar' => array(1, 2 => array('a', 'b'))), array('ar' => array(3, 4))) ;
print_r(ArrMd2Ud($arr));

Output:



Copy code

The code is as follows:

Array( [0] => 1 [1] => 2 [2] => 1

[3] => 2

[4] => 1
[5] => a
[6] => b

[7] => 3
[8] => 4
)

http://www.bkjia.com/PHPjc/741257.htmlwww.bkjia.comtruehttp: //www.bkjia.com/PHPjc/741257.htmlTechArticleMany times we need to convert multi-dimensional arrays into one-dimensional arrays, because we only need one-dimensional arrays, and one-dimensional Arrays are more convenient to use. How to convert multi-dimensional arrays into one-dimensional numbers in PHP...