I want to call a series of functions to build up an array, like so:

$array['conditions'][] = $this->function1($input1);
$array['conditions'][] = $this->function2($input2);
$array['conditions'][] = $this->function3($input3);

However, each function may return either an array with values or an empty array (depending on input). In the case of a returned empty array, $array['conditions'] is polluted with a bunch of empty entries, which is a problem when it comes to unit test maintenance - if I add additional functions I have to go back and update the expected value for all of my tests.

I could do something like:

$function1_return = $this->function1($input1);
if(!empty($function1_return) {
  $array['conditions'][] = $function1_return;

but I'm hoping there is a cleaner way? I also tried to remove any empty values after the fact, but to no avail (array_filter, for example, retains any array keys).

  • 2
    \$\begingroup\$ would array_values(array_filter($conditions)) help? I don't really get why array keys are that important for you though \$\endgroup\$ Commented Nov 21, 2018 at 15:39
  • \$\begingroup\$ @YourCommonSense I don't see how your proposed code solution will help, because as mentioned array_filter retains keys. The reason it's a problem is for the maintenance of tests - I have to keep adding extra empty keys to the expected array for each test as I add functions in the future. I will update my question to reflect this. \$\endgroup\$
    – Erebus
    Commented Nov 21, 2018 at 16:08
  • \$\begingroup\$ You want to keep empty keys and in same time drop them? That's totally unclear. \$\endgroup\$
    – Calak
    Commented Nov 21, 2018 at 16:19
  • \$\begingroup\$ @YourCommonSense jumped to a bad conclusion, apologies. Your code does indeed work perfectly! Please submit it as an answer and I will mark it as so. \$\endgroup\$
    – Erebus
    Commented Nov 21, 2018 at 16:31
  • \$\begingroup\$ @Erebus 1) It's unclear what you asked, 2) The code you presented in its current form is not meaningfully reviewable. We only review real, working code. If you edit your question to contain your actual code we can review it for improvements. See What topics can I ask about? for reference. \$\endgroup\$
    – Calak
    Commented Nov 21, 2018 at 16:31

1 Answer 1


The cleanest way is how you do and then filter:

$array['conditions'] = array_filter ($array['conditions']);

Or more explicitly (depend of your values):

$array['conditions'] = array_filter ($array['conditions'], function ($v){return !empty($v);});

And for normalizing indexes:

$array['conditions'] = array_values(array_filter($array['conditions']));
  • \$\begingroup\$ Thanks, but as I mentioned in the question, array_filter doesn't work as it retains keys. \$\endgroup\$
    – Erebus
    Commented Nov 21, 2018 at 16:12
  • \$\begingroup\$ Just use array_values as @YourCommonSense stated \$\endgroup\$
    – Calak
    Commented Nov 21, 2018 at 16:17

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