title: Ansible with_subelements default value
body: <p>i have a vars definition like this:</p>
  
  <pre><code>sites:
   - site: mysite1.com
     exec_init:
      - "command1 to exec"
      - "command2 to exec"
   - site: mysite2.com
  </code></pre>
  
  <p>then i have play with the following task</p>
  
  <pre><code>- name: Execute init scripts for all sites
    shell: "{{item.1}}"
    with_subelements: 
      - sites
      - exec_init
    when: item.0.exec_init is defined
  </code></pre>
  
  <p>The idea here is that i will have multiple "Site" definitions with dozens of other properties in my vars,
  then i would like to execute multiple Shell script commands for those sites having "exec_init" defined</p>
  
  <p>Doing it this way it just always skip executing the task, i've tried this in all combinations i can imagine but i just can't get it to work...</p>
  
  <p>Is this the proper way of doing it?  maybe i'm trying to achieve something that doesn't make sense?</p>
  
  <p>Thanks for your help</p>