Question

I have a collection of objects @users, each having its id attribute.

@users = [#<User id:1>, #<User id:2>]

I also have an ordered Array of ids.

ids = [2,1]

¿Is there a magical way to sort the collection using that list of ids? Without making another call to the database, if possible.

Thank you !!!

Answer 1

Try this. First, build up a reverse mapping from id -> user.

ids_users = {}

@users.each {|user| ids_users[user.id] = user}

Then, use the ids order

ids.collect{ |id| ids_users[id] }