2dto1d_cool.php

<?php
/**
 * Created by PhpStorm.
 * User: Computer Source
 * Date: 12/12/14
 * Time: 3:56 PM
 */

$array = array(
    array(554 => "a"),
    array(561 => "b"),
    array(574 => "c")
);
$array = array(
    array(554 => array(1,3,2)),
    array(561 => array(1,9,2)),
    array(574 => array(5,3,2))
);

$singleDimension=array_reduce($array,function($array,$item){return $array+$item;},array());
print '<pre>';
print_r($singleDimension);
print '</pre>';

// works good
echo 'merge';
$singleDimension2=call_user_func_array('array_merge',$array);
print '<pre>';
print_r($singleDimension2);
print '</pre>';

foreach(new RecursiveIteratorIterator(new RecursiveArrayIterator($array)) as $k=>$v){
    $singleDimension3[$k]=$v;
}
print '<pre>';
print_r($singleDimension3);
print '</pre>';

$result = array();
array_walk_recursive($array,function($v, $k) use (&$result){ $result[] = $v; });
print '<pre>';
print_r($result);
print '</pre>';

//keep keys, considers only the first element of every 2d array
$oneDimensionalArray = array_map('current', $array);

print '<pre>';
print_r($result);
print '</pre>';



$oneDimensionalArray = array_column($array);

print '<pre>';
print_r($oneDimensionalArray);
print '</pre>';

// PHP > 5.6:
$data = [[1, 2], [3], [4, 5]];
    print_r(array_merge(... $data)); // [1, 2, 3, 4, 5];


//PHP < 5.6:


$data = [[1, 2], [3], [4, 5]];
print_r(array_reduce($data, 'array_merge', []));   // [1, 2, 3, 4, 5];

?>