Using loops and lists (Must know)

This recipe explains the basics of lists and loops, creating a list of objects, and executing an action on each item.

How to do it...

1. Create a new rule configuration and set the Event to Node | After saving new content.

2. Add a Condition, Node | Content is of type and set it to Article.

3. Add a new loop and set Data selector to node:field-tags.

4. Add a new Action System | Show a message on the site and set a message.

   

How it works...

Using lists and loops in Rules is the way to handle multiple value fields and execute Actions on each individual item. While this particular recipe is not too useful in the real world, it can be used as a basis for more advanced features, for example, when using a node reference field to provide reference to a list of related nodes. We can then load that list of referenced nodes and create a loop that will send a customized e-mail notification to the authors of the referenced nodes.

There's more...

We can also add items to a list by adding an Action, Data | Add an item to a list. An example use case could be to automatically add a taxonomy term to the newly created node or add a user to a user reference list.