在将每个变量添加到数组之前验证它们是否存在

I'm pulling data from a dozen different text fields into a single multidimensional array, but I would like for a key to only be created if there are elements to add to it. Example:

$colors = array(
  'red'     => $options['red_users'],
  'orange'  => $options['orange_users'],
  'green'   => $options['green_users']
);

Let's say there is no data in the 'orange_users' input field. Other than running a conditional check on each variable, e.g...

if (!$options['orange_users']) {

...how can I efficiently validate that data exists for each input field I'm pulling from?

The easiest way to do this is with a ternary if

  $replacements = array(
    'red'     => isset($vbulletin->options['red_users'])?$vbulletin->options['red_users']:null,
    'orange'  => isset($vbulletin->options['orange_users'])?$vbulletin->options['orange_users']:null,
    'green'   => isset($vbulletin->options['green_users'])?$vbulletin->options['green_users']null
  );

Then to weed out the empty values just use array_filter

  $replacements = array_filter($replacements);