The array_column() function I wrote myself that is compatible with versions lower than PHP 5.5, 5.5array_column_PHP tutorial

The array_column() function written by myself is compatible with versions lower than PHP 5.5, 5.5array_column

array_column is used to obtain elements in a two-dimensional array (new function in PHP 5.5), but we sometimes need to use it in a lower version of PHP environment...

if( ! function_exists('array_column'))
{
  function array_column($input, $columnKey, $indexKey = NULL)
  {
    $columnKeyIsNumber = (is_numeric($columnKey)) ? TRUE : FALSE;
    $indexKeyIsNull = (is_null($indexKey)) ? TRUE : FALSE;
    $indexKeyIsNumber = (is_numeric($indexKey)) ? TRUE : FALSE;
    $result = array();

    foreach ((array)$input AS $key => $row)
    { 
      if ($columnKeyIsNumber)
      {
        $tmp = array_slice($row, $columnKey, 1);
        $tmp = (is_array($tmp) && !empty($tmp)) ? current($tmp) : NULL;
      }
      else
      {
        $tmp = isset($row[$columnKey]) ? $row[$columnKey] : NULL;
      }
      if ( ! $indexKeyIsNull)
      {
        if ($indexKeyIsNumber)
        {
          $key = array_slice($row, $indexKey, 1);
          $key = (is_array($key) && ! empty($key)) ? current($key) : NULL;
          $key = is_null($key) ? 0 : $key;
        }
        else
        {
          $key = isset($row[$indexKey]) ? $row[$indexKey] : 0;
        }
      }

      $result[$key] = $tmp;
    }

    return $result;
  }
}

The following are the installation steps I found online. I have never configured it under apache.
If you don’t want to bother, you can download a ready-made component, such as PHPnow, which integrates apache+php+mysql+Zend Optimizer+eAccelerator Everything that needs to be configured is integrated, just install it
Of course it is 2003

To be able to run on both php4 and php5, you need to have a version judgment function

You can do this:
if (version_compare( phpversion(), ' 5', '<' ) )
include_once( 'php4.php' ) ;//php4 related configuration files or calling functions
else
include_once( 'php5.php' ) ;//php5 Related files or calling functions
}
In this way, in different environments, you can call different files to realize your functions, but the specific implementation is much more complicated.
Hope it helps you