Error when I edit a block: Notice: Undefined index: und in eval()

Question

I don't understand why I put $node->field_test['und'][0]['value'] appears the next error:

Notice: Undefined index: und in eval()

The field "field_test" is a boolean field. The code is the following one:

$node = node_load(153);    
if ($node->field_test['und'][0]['value'] == 1) { 
  echo "test";
}

What is my error?

Answer 1

You must pay attention to the node's language. 'und' is for nodes which don't have a language set. If you set one, then the values will be in 'en' or 'de' or whatever the node's language code is.

Answer 2

Don't assume that 'und' is for fields of entities without language, it is also for fields that are not translatable, and without the entity translation module that is all fields. Moreover, there are differences in this between the various 7.x versions of Drupal.

Better to use the field_get_items() function which will sort out for you under what language code the data is stored.

Answer 3

I found the answer.

I had to change the code:

 <?php
    $node = node_load(153);    
    if ($node->field_test[$node->language][0]['value'] == 1) { 
    echo "test";
    }

I replaced it with the following one:

    $node = node_load(153);    
if (isset($node->field_test[$node->language][0]['value']) && $node->field_test[$node->language][0]['value'] == 1) { 
  echo "test";
}

This code solved the error and works for me.