PHP Sort an array alphabetically except ONE value on top, for a dropdown menu

Question

I am trying to hack a dropdown menu pulling info from an array of countries so that 'United States' (id 1) appears on the top, while every other country is sorted by alphabetical order. How do I sort all EXCEPT United States to remain on top, using usort function for an array? Any alternative suggestions are also welcome. Here is the code:

while (list($key, $value) = each($countries->countries)) {
   $countries_array[] = array('id' => $key, 'text' => $value['countryname']);
}
function text_cmp($a, $b) {
   return strcmp($a["text"], $b["text"]);
} 
usort($countries_array, 'text_cmp'); 

Answer 1

The easiest way to do this is to remove the single value, sort and then re-add it:

working example

// your countries array goes here:
$countries = array(2=>"Burma", 4=>"Zimbabwe", 10=>"France", 1=>"United States", 13=>"Russia");

$AmericaFKYeah = array(1=>"United States");
$countries =array_diff($countries, $AmericaFKYeah);
asort($countries);

// using + instead of array_unshift() preserves numerical keys!
$countries= $AmericaFKYeah + $countries;

gives you:

array(5) {
  [1]=>
  string(13) "United States"
  [2]=>
  string(5) "Burma"
  [10]=>
  string(6) "France"
  [13]=>
  string(6) "Russia"
  [4]=>
  string(8) "Zimbabwe"
}

Answer 2

With Indexed Array

Steps

1. Find resource in array
2. Unset variable in array
3. Add resource as the first element in array with array_unshift (array_unshift — Prepend one or more elements to the beginning of an array - http://php.net/manual/en/function.array-unshift.php)

Code

 if (in_array('yourResource', $a_array)){
    unset($a_array[array_search('yourResource',$a_array)]);
    array_unshift($a_array, 'yourResource');
 }

With MultiDimensional Arrays

$yourResorceToFind = 'yourResource';
foreach ($a_arrays as $a_sub_array){
  if (in_array($yourResorceToFind, $a_sub_array)){

    unset($a_arrays[array_search($yourResorceToFind,$a_sub_array)]);
    array_unshift($a_arrays, $a_sub_array);
    break;
  }
}