如何对array_merge（）函数的结果进行排序？

Question

Here is my code :

<?php

$arr1 = ['o' => 'vote', 'u' => 'true'];
$arr2 = ['p' => '', 'v' => 'digit'];

print_r(array_merge($arr1, $arr2));

/* Array
   (
       [o] => vote
       [u] => true
       [p] => 
       [v] => digit
   )

Always there is one item which has empty value. In example above, that item is p . Now I need to put that item as the last one. How can I do that?

Note: I don't care about the order of other items.

---

So this is expected result:

/* Array
   (
       [o] => vote
       [u] => true
       [v] => digit
       [p] => 
   )

Answer 1

One possible approach that preserves the order of non-empty elements would be:

$arr1 = ['o' => 'vote', 'u' => 'true'];
$arr2 = ['p' => '', 'v' => 'digit'];

$merged = $arr1 + $arr2;

$empty = array_filter($merged, function($var) {
    return $var == "";
});

$nonEmpty = array_diff_assoc($merged, $empty);

$sorted = $nonEmpty + $empty;

Answer 2

function sort($array){
        $emptyKey ="";
        foreach ($array as $key => $value){
             if(empty($value){
                  $emptyKey = $key;
                   break;
             }
        }
        unset($array[$emptyKey]);
        $array[$emptyKey] = "";
        return $array;
}

Answer 3

One simple way I found was to use rsort , which Sort an array in reverse order . Like so ( run ):

$merged = array_merge($arr1, $arr2);
rsort($merged);

The output:

Array
(
    [0] => vote
    [1] => true
    [2] => digit
    [3] => 
)

You could also go with a simple foreach ( example ) or even usort ( example )