anchor.diff:  
   == Jinja Filters
   
  -The main tool for this purpose are Jinja filters. There are 2 libraries of filters available:
  +The main tool to transform Ansible variables are Jinja filters. There are 2 libraries of filters available:
   
   * The Jinja http://jinja.pocoo.org/docs/2.10/templates/#list-of-builtin-filters[builtin filters].
     This list can also be found in Ansible source code https://github.com/pallets/jinja/blob/master/jinja2/filters.py[filters.py].
  
positive.code: 
  As a Java developer, I sometimes dream that I can use the Java 8+ Stream API in my Ansible playbook to process list and dict variables.
  
  [source,yaml]
  ----
  include::{source_dir}/group_vars/all.yml[tags=list_var]
  
negative.code: ----
  include::{source_dir}/group_vars/all.yml[tags=map_advanced]
  ----
  <1> For each `users` take its name and when the regular expression matches  apply the replacement, then join the result.
  
  == JSON Query
  
  Another strategy is to use a JSON Path to walk down the YAML tree.
  It's bit less verbose and bit more powerful than the previous solution.
  
  ----
  include::{source_dir}/group_vars/all.yml[tags=json_query]
  