ansible parse extra var use default if regex fails

Question

I have the following code which isn't throwing an error but the fact is empty

 - shell: echo '{{ p }}'
 register: results
 - debug:
 var: results
 - set_fact:
 myrepo: "{{ results.stdout | regex_search(regexp,'\1円') | default ( {'0':'global'} ) }}"
 vars:
 regexp: '(.*)/(.*)'

Here is the output

TASK [command] **************************************************************************************************************************************************************************************
changed: [localhost]
TASK [debug] ****************************************************************************************************************************************************************************************
ok: [localhost] => {
 "results": {
 "changed": true, 
 "cmd": "echo 'tim'", 
 "delta": "0:00:00.095831", 
 "end": "2017-09-06 16:37:19.977023", 
 "rc": 0, 
 "start": "2017-09-06 16:37:19.881192", 
 "stderr": "", 
 "stderr_lines": [], 
 "stdout": "tim", 
 "stdout_lines": [
 "tim"
 ]
 }
}
TASK [set_fact] *************************************************************************************************************************************************************************************
ok: [localhost]
TASK [debug] ****************************************************************************************************************************************************************************************
ok: [localhost] => {
 "myrepo": ""
}

The command is ansible-playbook -i hosts -c local file.yml --extra-vars "p=tim" I want myrepo to be global if the regex results are empty

Answer 1

Without any parameters default filter is triggered only when value is Undefined. But result of unmatched regexp is an empty string, which is not Undefined. You may want to set boolean flag:

 - set_fact:
 myrepo: "{{ results.stdout | regex_search(regexp,'\1円') | default('global', boolean=True) }}"
 vars:
 regexp: '(.*)/(.*)'