Order Users List by Last Entry Date I am trying to order a list of Users by the date of their last entry. order('postDate desc') works for entries of course, but I can't find a way to order the Users of those posts based on their latest post date. This is the code I am using now which orders the User by the date their account was created.    

{# Grab all the Design Entries #}
{% set allDesigns = craft.entries.section('designs').limit(null).find() %}

{# Group by the authorId #}
{% set allDesignsByAuthorId = allDesigns|group('authorId') %}

{# Grab all of the users with the userIds in allDesignsByAuthorId #}
{% set designers = craft.users.group('designers').id(allDesignsByAuthorId|keys).order('dateCreated desc') %}


Thank you in advance for any help you can give!
I just noticed that you've posted an answer to your question already.

Your approach using the group filter is probably all you need, as the allDesigns array is sorted by postDate desc and by using the group filter you'll keep that sort order, your author IDs and the nested entries will both be sorted by the design post date.

To query the user models in the order of the IDs passed to the id param, you just need to add the fixedOrder param to your craft.users criteria model.

{# Grab all the Design Entries #}
{% set allDesigns = craft.entries.section('designs').limit(null).find() %}

{# Group by the authorId #}
{% set allDesignsByAuthorId = allDesigns|group('author.id') %}

{# Grab all of the users with the userIds in allDesignsByAuthorId #}
{% set designers = craft.users.group('designers').id(allDesignsByAuthorId|keys).fixedOrder(true) %}