In my entityform, different fields appear based on choices (dependencies). Two appear at once. I'm multiplying the values using a Computed field. All works if the variables have a value. I have 8 fields I want to multiply, but ignore the empty values. Can't set field defaults to 0 (wrecks multiplication) or 1 (messes with totals).

The following warning appears for each empty field; here it's "line 1" for the 1st variable/field. No warning for those that have a value.

Warning: array_pop() expects parameter 1 to be array, null given in eval() (line 1 of /home/content/67/10793667/html/sites/all/modules/computed_field/computed_field.module(466) : eval()'d code).

How can I instruct the computed field to ignore the empty fields?

Here is my Computed Code (PHP).

$howmany = array_pop(array_pop(field_get_items($entity_type, $entity, 'field_how_many')));
$price1 = array_pop(array_pop(field_get_items($entity_type, $entity, 'field_reg_price1')));
$price2 = array_pop(array_pop(field_get_items($entity_type, $entity, 'field_sale_price2')));
$entity_field[0]['value'] = $howmany*$price1*$price2;

I tried adding this after the $price2 line, but it didn't work.

if ($price2 == null) {
    $price2 = 1;

I tried this too, and it didn't work.

if (!empty($price2)) {
  $price2 = 1;
else {
  $price2 = array_pop(array_pop(field_get_items($entity_type, $entity, 'field_sale_price2')));

Both @Neo's answer and @danielesus's question shows PHP code that will throw errors. @Neo, empty() only works with variables before PHP 5.5. Both: array_pop requires a variable or something returned by a reference-returning-function which field_get_items is not.

Now let's consider what field_get_items($entity_type, $entity, 'field_how_many') returns: it returns an array indexed by delta where the values are field_column => value. You can do

if ($all_items = field_get_items($entity_type, $entity, 'field_how_many')) {
  $item = reset($all_items);
  $value = reset($item);

as there's no need to actually modify the array with array_pop but also you can use your knowledge about Field API and know the actual column name which I suspect will be value here (would be tid for a taxonomy reference field for example) and that $delta is, if you have a field with cardinality 1 is actually 0:

$value = NULL;
if ($all_items = field_get_items($entity_type, $entity, 'field_how_many')) {
  $value = $all_items[0]['value'];

Fast and simple.

$howmany = !empty(field_get_items($entity_type, $entity, 'field_how_many')) ? array_pop(array_pop(field_get_items($entity_type, $entity, 'field_how_many'))) : 1; 

$price1 = !empty(field_get_items($entity_type, $entity, 'field_reg_price1')) ? array_pop(array_pop(field_get_items($entity_type, $entity, 'field_reg_price1'))) : 1; 

$price2 = !empty(field_get_items($entity_type, $entity, 'field_sale_price2')) ? array_pop(array_pop(field_get_items($entity_type, $entity, 'field_sale_price2'))) : 1; 

$entity_field[0]['value'] = $howmany*$price1*$price2;

If this still does not work, Please try to inspect the structure of the stuff returned by field_get_items(). I am pretty sure the issue lies in returning a null from the fist array_pop.

In order to inspect the structure, add these lines to your compute code after enabling and installing devel module:

dpm(field_get_items($entity_type, $entity, 'field_how_many')); dpm(field_get_items($entity_type, $entity, 'field_reg_price1')); dpm(field_get_items($entity_type, $entity, 'field_sale_price2')));

  • Hi Neo, thanks so much for your quickly reply. Been testing almost immediately, getting the same results as before, same Warning on empty fields. Using the code you gave, with only 2 fields (e.g., $howmany and $price1) works as before with computed value appearing correctly. I get the same error when I add a 3rd variable that is an empty field - and the results shows 0, most likely due the multiplication with empty field. – danielesus Oct 4 '13 at 14:32
  • modified the code. Please see if this works. – Neo Oct 4 '13 at 14:41
  • Same results, same Warning. Works fine with just 2 fields, computed value - great. As soon as I add a 3rd, get the error and 0 value. – danielesus Oct 4 '13 at 15:01
  • ok I think I figured out the issue. the issue lies in the two array_pop s. In case of an empty field, the first array_pop returns null. And hence the second one gets null as parameter. Updated my answer accordingly. – Neo Oct 4 '13 at 15:50
  • On form submission, get a WSOD with Fatal error on line 1: Fatal error: Can't use function return value in write context in /home/content/67/10793667/html/sites/all/modules/computed_field/computed_field.module(466) : eval()'d code on line 1 – danielesus Oct 4 '13 at 16:37

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