Remove array entry

  //Remove specific index from array
  unset($MyArray['SomeName']);

  //Remove first index from array 
  $IndexValue = array_shift($MyArray);

  //Remove last index from array
  array_pop($MyArray);

Inserting New Entry into array

Insert at index 0

The rest of the array entries move down if there is already a [0] entry

  $Results = db_device_read_all_devices();
  if ($Results != False)
  {
    //Insert our coumn titles into the Results array as index 0 (the rest of the array moves down)
    $ColumnTitles = array(
      "DeviceId"=>"Device ID",
      "Name"=>"Name",
      "CreatedDateTime"=>"Created",
      "LastConnected"=>"Last Connected",
      "SoftwareVersion"=>"Software Version",
      "Notes"=>"Notes"
    );
    array_unshift($Results,$ColumnTitles);

You can insert mutliple entries at the start of the array if you wish, e.g.
$MyArray = ["ab", "cd"];
array_unshift($MyArray, "ef", "gh");

Sort Array

https://www.w3schools.com/php/php_arrays_sort.asp

Sort by array key

ksort() sorts an associative array in ascending order, according to the key

  $age = array("Peter"=>"35", "Ben"=>"37", "Joe"=>"43");
  ksort($age);