From time to time, I need to dynamically build a list of strings (or a list of other things) using Ansible's
set_fact is a module like any other, you can use a
with_items loop to loop over an existing list, and pull out a value from that list to add to another list.
For example, today I needed to retrieve a list of all the AWS EC2 security groups in a region, then loop through them, building a list of all the security group names. Here's the playbook I used: