Question

I have one array, which are IDs from one ActiveRecord table.
so I would like to sort that array based on last name which is associated with that ID…how can I do that?
To clarify:
array @students=[], inside are IDs and I would like to sort by Student.find(ID).last
Thank you.
Dorijan

Answer 1

Without fully understanding the question, if you’re given a list of id’s, you can sort by last_name when you’re doing the query:

Student.where("id IN (?)", @students).order(:last_name)

Of course, this assumes that @students is an array of ids and nothing else.

Responding to your comment, I’m not sure why you’d need to do that, but if your @student array is just a list of ids ignorant of the Student model and its attributes, and you would still like to order that array, you can do this:

@students = Student.where("id IN (?)", @students).order(:last_name).collect(&:id)

This will return an array of ids sorted by last name. But again, I don’t really know what you have going on behind the scenes, and I’m not sure what you’re asking for.